Hydrostatic Power Train

Transcription

1 Chapter Hydrostatic Power Train Specifications Test Specifications Repair Specifications Hydraulic Hose, Tube, and Fitting General Instructions O-Ring Installation Hydraulic Hose Installation Hydraulic Service Tools Portable In-Line Filter Digital Hydraulic Tester Hydraulic Flow Meter Digital Pressure Gauge Kit Hydraulic Hose Kit Hydraulic Test Fitting Kit Blocking Disk Set Component Location Theory of Operation and Sub-Circuit Schematics Traction Circuit Neutral Schematic and Theory of Operation (4WD Models) Traction Circuit Neutral Schematic (4WD Models) Traction Circuit Forward Schematic and Theory of Operation (4WD Models) Traction Circuit Forward Schematic (4WD Models) Traction Circuit Reverse Schematic and Theory of Operation (4WD Models) Traction Circuit Reverse Schematic (4WD Models) Traction Circuit Neutral Schematic and Theory of Operation (WD Models) Traction Circuit Neutral Schematic (WD Models) Traction Circuit Forward Schematic and Theory of Operation (WD Models) Traction Circuit Forward Schematic (WD Models) Traction Circuit Reverse Schematic and Theory of Operation (WD Models) Traction Circuit Reverse Schematic (WD Models) Troubleshooting Tests and Adjustments Neutral Adjustments Rev B -

2 Field Test Procedures Preliminary Checks Traction System Test Wheel Motor Test Brake System Test Instrument Test Procedures Instrument Test Overview Charge Pressure Test Traction System Test Traction Pump Tests Front Wheel Motors Tests WD Test Rear Wheel Motors Tests Repair Drive Shaft Traction Pump Brake Release WD Front Wheel Motor (Earlier Machines) Front Wheel Motor (Later Machines) Front Axle Assembly Rear Wheel Motor Rev B

3 Specifications Test Specifications Specification Traction Pump Flow gpm (lpm) 38.3 (4) at 30 rpm Forward System Relief Pressure psi (bar) 36 ± 0% (0 ± 0%) at 30 rpm Machine Serial Numbers Ending 6 Through 499 Forward System Relief Pressure psi (bar) 430 ± 0% (300 ± 0%) at 30 rpm Machine Serial Numbers Ending 00 and Up Reverse System Relief Pressure psi (bar) 36 ± 0% (0 ± 0%) at 30 rpm Charge Pressure psi (bar) 3 ± 0% ( ± 0%) at 30 rpm Hydrostatic Leakage Percentage Ranges 0 0% = Good 0% = Marginal % and Beyond = Bad Repair Specifications Specification Drive Shaft Mounting Screw Torque lb-ft (N m) 3 40 (47 4) Traction Pump Test Port Fitting Torque lb-ft (N m) 7 (3) Traction Pump Return Tube Fitting Torque lb-ft (N m) 80 (08) Traction Pump Charge Filter Tube Fitting Torque lb-ft (N m) 60 (8) Traction Pump Ports A and B Fitting Torque lb-ft (N m) 00 (3) Traction Pump System Relief s Torque lb-ft (N m) 30 (76) Traction Pump Charge Pressure Relief Screw lb-ft (N m) 80 (08) Torque Traction Pump Tow Torque lb-ft (N m) (0) Traction Pump Front Cover Screw Torque lb-ft (N m) 43 (8) Traction Pump Cover Plate Screw Torque lb-ft (N m) 7 (77) Traction Pump Auxiliary Pad Screw Torque lb-ft (N m) 3 (43) Traction Pump Case Outlet Plug Torque lb-ft (N m) 8 () Traction Pump Plug Torque lb-ft (N m) (0) Traction Pump Servo Piston Cover Plug Torque lb-ft (N m) 7 (37) Traction Pump Servo Piston Cover Screw Torque lb-ft (N m) () Traction Pump Seal Nut Torque lb-ft (N m) 7 (37) Traction Pump EDC Mounting Screw Torque lb-ft (N m) 0 (4) Traction Pump Filtration Cover Screw Torque lb-ft (N m) (30) Traction Pump Filtration Cover Plug Torque lb-ft (N m) 7 (37) Brake Release Coil Nut Torque lb-in. (N m) 33 3 (4 6) Brake Release Ports ST and BR Fitting lb-ft (N m) 7 (3) Torque Brake Release CHG and DRN Ports Fitting lb-ft (N m) 7 (3) Torque Brake Release Direction Control Torque lb-ft (N m) 30 3 ( ) 446-Rev B -3

4 Specification Brake Release Direction Control Nut lb-in. (N m) (4. 6.8) Torque Brake Release Coil Nut Torque lb-in. (N m) 3 3 (4 6) Brake Release Solenoid Torque lb-ft (N m) 6 30 ( ) Brake Release Relief Torque lb-ft (N m) 0 ( ) Brake Release Check Torque lb-ft (N m) 0 ( ) 4WD Ports LRF, LRR, RRF, and RRR lb-ft (N m) 0 (49) Fitting Torque 4WD Ports LF and RF Fitting Torque lb-ft (N m) 0 (49) 4WD DRN Port Fitting Torque lb-ft (N m) (34) 4WD REV Port Fitting Torque lb-ft (N m) 60 (7) 4WD Check Torque lb-ft (N m) 30 3 ( ) 4WD Hot Oil Shuttle Torque lb-ft (N m) 30 3 ( ) 4WD Relief Torque lb-ft (N m) 30 3 ( ) Front Wheel Motor Mounting Screw Torque lb-ft (N m) 8 9 ( 9) Machine Serial Numbers Ending 6 Through 499 Front Wheel Motor Mounting Flange-to-Bearing lb-ft (N m) 7 (37) Housing Screw Torque Machine Serial Numbers Ending 6 Through 499 Front Wheel Motor Case Drain and Brake Release lb-ft (N m) (0) Port Fitting Torque Machine Serial Numbers Ending 6 Through 499 Front Wheel Motor Inlet and Outlet Port Fitting lb-ft (N m) 0 (49) Torque Machine Serial Numbers Ending 6 Through 499 Front Wheel Motor End Cover Screw Torque lb-ft (N m) (70) Machine Serial Numbers Ending 6 Through 499 Front Wheel Motor Mounting Nut Torque lb-ft (N m) 90 () Machine Serial Numbers Ending 00 and Up Front Wheel Motor Case Drain Fitting Torque lb-ft (N m) 30 (4) Machine Serial Numbers Ending 00 and Up Front Wheel Motor Brake Release Port Fitting lb-ft (N m) 7 (3) Torque Machine Serial Numbers Ending 00 and Up Front Wheel Motor Inlet and Outlet Port Fitting lb-ft (N m) 90 () Torque Machine Serial Numbers Ending 00 and Up Front Wheel Motor Bearing Support Rotation lb-ft (N m) 8.8 ± 30% ( ± 30%) Torque Machine Serial Numbers Ending 00 and Up Front Wheel Motor Valving Cover to Cam Ring lb-ft (N m) 6 ± 0% (83 ± 0%) Screw Torque Machine Serial Numbers Ending 00 and Up Front Wheel Motor Brake Housing to Valving Cover lb-ft (N m) 07 ± 0% (4 ± 0%) Screw Torque Machine Serial Numbers Ending 00 and Up Front Axle Mounting Screw Torque lb-ft (N m) 8 ( 30) Rev B

5 Specification Rear Wheel Motor Mounting Screw Torque lb-ft (N m) ( 36) Rear Wheel Motor Inlet and Outlet Port Fitting lb-ft (N m) 90 () Torque Rear Wheel Motor Case Drain Fitting Torque lb-ft (N m) (0) Rear Wheel Motor Housing Screw Torque lb-ft (N m) (49 0) 446-Rev B -

6 Hydraulic Hose, Tube, and Fitting General Instructions O-Ring Installation Always install new O-rings. On hoses with O-ring fittings, make sure O-rings are properly seated before tightening. O-rings should be lubricated with the fluid to be used in the system prior to assembly. Boss Fitting O-Ring Installation 3 TN407 Tubing O.D. or Hose I.D. O-Ring 3 Thread Size O-Ring Seal Kits SAE Boss O-Ring Kit Jacobsen PN 004 O-Ring Face Seal (ORS) O-Ring Kit PN 0044 Common O-Ring Sizes Kit PN 0043 Replacement O-Rings for ORS (Face Seal) Fittings ORS (Face Seal) Tube Size ORS (Face Seal) O-Ring Size Jacobsen Part Number TN4097 Replacement O-Rings for O-Ring Boss Fittings Tubing O.D. or Hose I.D. Thread Size Hydraulic Hose Installation Jacobsen Part Number /8 / /6 3/ /4 7/ /6 / /8 9/ / 3/ /8 7/ /4 -/ /8-3/ / /4 -/ / -7/ / Hold the fixed portion of the hose coupling with one wrench; use a second wrench to tighten or loosen the hose nut. This will avoid damaging the fitting seal. When tightening a hose, do not permit the hose to twist; hold the hose in a normal straight position. When installing hoses, place fittings at angles to avoid contact with fixed parts when turning. Make sure hoses are assembled to proper A and B ports on components. Hydraulic Hose and Tube Torque Values Size lb-ft N m Dash Fractional Min Max Min Max -4 / / / / / / / Rev B

7 Hydraulic Service Tools The hydraulic service tools listed here can be obtained from K-Line Industries at Digital Hydraulic Tester Part Number AT4003 Portable In-Line Filter Part Number JAC097 TN488 When hydraulic components fail internally, debris from the failed component can spread throughout the hydraulic system and cause additional damage. This situation can be magnified when dealing with a closed-loop traction system, where oil is not filtered. In the event of a traction system component failure, it is recommended that all traction system components be disassembled and cleaned, or filtered using a portable in-line filter available through your Jacobsen Dealer. The portable in-line filter should also be used when testing hydraulic systems or after replacing a failed component. IMPORTANT TN486 Always install the in-line filter so oil flows through the filter before entering a component. Once filtering has begun, never reverse the flow of oil, or debris will re-enter the system. Features Flow up to 00 gpm (379 lpm) Pressure up to 6000 psi (44 bar) Temperature up to 0 F (0 C) Digital display for flow and temperature Analog display for pressure Flow accuracy % of full scale Hydraulic Flow Meter Part Number AT4000 TN487 Features Glycerin filled pressure gauge Precision needle-type load valve 4 40 gpm ( lpm) flow range Pressure up to 000 psi (34 bar) - port size 446-Rev B -7

8 Digital Pressure Gauge Kit Part Number JAC06 Hydraulic Test Fitting Kit Part Number JAC00A Features Quick disconnect fittings Pressure up to 000 psi (34 bar) Includes one ft ( cm) hose Hydraulic Hose Kit Part Number JAC00H This hydraulic hose kit is intended to be used with the JAC00A Hydraulic Test Fitting Kit. Contents TN490 Two 8 ft (44 cm) ORFS (F) x 0 ORFS (F) hoses Four 8 ft (44 cm) 0 ORFS (F) x 0 ORFS (F) hoses Two 8 ft (44 cm) 8 ORFS (F) x 0 ORFS (F) hoses For detailed component descriptions and sizes, please see the K-Line Industries website at Contents Twenty ORFS tee fittings in five sizes Eight ORFS 90 elbow fittings in four sizes Forty ORFS caps in five sizes Forty ORFS plugs in five sizes Six ORS reducer adapters in three sizes Sixteen ORS adapters in four sizes Eight blocking disks in four sizes Three JIC tee fittings in three sizes Three 4 in. (0 mm) jumper hoses in three sizes One ORS/male NPTF adapter One vented bushing One copper tube assembly Blocking Disk Set Part Number JAC00- TN489 This blocking disk set is part of the JAC00A Hydraulic Test Fitting Kit. Contents Two -6 blocking disks Two -8 blocking disks Two -0 blocking disks Two - blocking disks Two -6 blocking disks Rev B

9 Component Location See Figure Brake Release 3 Gear Pump Rear Axle Motors 7 Front Axle Motors Hydrostatic Pump 4 4WD 6 Drive Shaft Figure -: Component Location Left Side TN386,TN368,TN369, TN Rev B -9

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11 Theory of Operation and Sub-Circuit Schematics Traction Circuit Neutral Schematic and Theory of Operation (4WD Models) System Conditions: Engine running Park brake switch in the on position (park brake engaged) Traction pedal in the neutral position Charge Pressure Circuit The traction pump and gear pump are both driven by the engine. Section of the gear pump provides charge pressure oil for the rear reel circuit and the traction pump. Hydraulic oil is drawn from the hydraulic tank through a 00-mesh screen, and enters the gear pump, supplying oil to all three pump sections. Oil from section of the gear pump is routed through the rear reel valve to the charge filter. The charge filter uses a 0-micron filter to remove debris from the oil. In the event of the charge filter becoming plugged, a psi (.7 bar) pressure switch will activate the Low Hydraulic Oil Filter message and LED warning light on the LCD display, and the charge filter will be bypassed. Charge pressure oil is then routed to the hydrostatic traction pump. Charge pressure oil is also routed to the CHG port of the brake release valve. Traction Pump Circuit With the traction pedal in the neutral position, the EDC (electronic displacement control) valve is in the neutral position and oil pressure in both pilot lines to the control sleeve is equal. Since pressure is equal on both sides of the control sleeve, the control sleeve is centered in the neutral position. Oil is not supplied to the servo pistons and no movement of the swashplate occurs. The charge oil is supplied to the closed-loop traction circuit via the check valves and exits the traction pump at ports A and B. Oil from port A is routed in parallel to the front wheel motors. Oil from port B is routed to the REV port of the 4WD valve. The oil flows against the hot oil shuttle and is then routed in parallel against the RRF and LRF check valves to the rear wheel motors. Oil exiting the right rear motor flows against the RRF check valve, against the 400 psi (8 bar) LF relief valve and pilot line of the LF relief valve, against the 400 psi (8 bar) RF relief valve, exits the 4WD valve at port LF, and is routed to the left front wheel motor. Oil exiting the left rear motor flows against the LRF check valve, against the pilot line of the hot oil shuttle, against the 400 psi (8 bar) LF relief valve, against the 400 psi (8 bar) RF relief valve and pilot line of the RF relief valve, exits the 4WD valve at port RF, and is routed to the right front wheel motor. Since pressure is equal on both sides of the front wheel motors, no movement occurs. With the closed-loop circuit charged with oil, the 3 psi ( bar) charge pressure relief valve will open and vent excess oil to the hydraulic tank. Hydraulic oil is used to lubricate the internal components of pumps and motors. This oil is returned via the case drain lines back to the hydraulic tank. Park Brake Circuit The front wheel motors are equipped with multi-disk wet brakes. The brakes are spring-applied, and released with pressurized oil controlled by the brake solenoid valve and the brake release valve. Towing Mode The park brake circuit is equipped with a lever-operated brake release valve to allow the release of the brakes with a dead engine for towing purposes. When the brake release lever is moved to the released position, the oil passage in the brake release valve is opened to the steering cylinder. This oil pathway provides a means to release the brakes with the engine off by turning the steering wheel, routing oil from the steering circuit to the brake cylinders to release the brakes. 446-Rev B -

12 Traction Circuit Neutral Schematic (4WD Models) See Figures - and -3. REV Test Port M B 30 ±0 rpm.8 ci Check Reverse Relief 36 psi 0.0 ci Gear Pump 0.0 ci 0.0 ci STRG Test Port Tow Check Forward Relief (See Note) 3 M M in in. Traction Pump A 3 4 Screen 40 Mesh L Control Sleeve Charge Pressure Relief 3 psi L FOW Test Port M M3 0 Micron Filter psi Switch Charge Filter 6 EDC psi Crack Bypass Micron Filter 9 psi Crack Bypass Return Filter Tank Fill Cap Assembly Oil Cooler psi Crack Bypass Suction Screen 00 Mesh 0 Micron Filter Hydraulic Tank Charge Pressure Oil Metered Oil Inlet or Drain Oil Return Oil Return Oil to Steering Unit (Port P) 4 Charge Pressure Oil to Rear Reel (Port P) 7 Return Oil from Rear Wheel Motors Case Drains, 4WD (DRN Port), and Reel Motors Case Drains Charge Pressure Oil to 4WD (REV Port) Return Oil to Front Reel (Port P) 8 Return Oil from Front Reel (Port T) 3 Charge Pressure Oil to Front Axle Motors Note: Forward relief valve pressure is 36 psi for machines with serial numbers ending 6 through 499. Forward relief valve pressure is 430 psi for machines with serial numbers ending 00 and up. 6 Charge Pressure Oil from Rear Reel (Port T) 9 Charge Pressure Oil to Brake Release (CHG Port) Figure - TN Rev B

13 Traction Circuit Neutral Schematic (4WD Models), Continued Reverse Left Front Wheel Motor Right Front Wheel Motor (See Note) Brake Cylinder Brake Cylinder (See Note) RF REV LF RF Relief 400 psi 3 4 Forward 4WD LF Relief 400 Hot Oil Shuttle DRN 6 RRR 0.0 in. Right Rear Wheel Motor RRF RRF Check LRF Check.90 ci.90 ci LRF LRR Left Rear Wheel Motor 7 9 DRN Relief 30 psi BR Brake Release A B 0 Check ST Solenoid Backlap CHG Brake Solenoid Rear Reel Test Port G Rear Reel P T Charge Pressure Oil Charge Pressure Oil from Traction Pump (Port B) 3 Charge Pressure Oil from Traction Pump (Port A) 4 Charge Pressure Oil from Section of Gear Pump Note: Front wheel motor displacement is 9.3 ci for machines with serial numbers ending 6 through 499. Front wheel motor displacement is 7.09 ci for machines with serial numbers ending 00 and up. 6 Charge Pressure Oil to Charge Filter 0 Case Drain Oil from Reel Motors 7 Return Oil to Hydraulic Tank Return Oil from Rod End of Steering Cylinder 9 Charge Pressure Oil from Charge Filter Figure -3 TN Rev B -3

14 Traction Circuit Forward Schematic and Theory of Operation (4WD Models) System Conditions: Engine running Park brake switch in the off position (park brake disengaged) Traction pedal in the forward position Charge Pressure Circuit The traction pump and gear pump are both driven by the engine. Section of the gear pump provides charge pressure oil for the rear reel circuit and the traction pump. Hydraulic oil is drawn from the hydraulic tank through a 00-mesh screen, and enters the gear pump, supplying oil to all three pump sections. Oil from section of the gear pump is routed through the rear reel valve to the charge filter. The charge filter uses a 0-micron filter to remove debris from the oil. In the event of the charge filter becoming plugged, a psi (.7 bar) pressure switch will activate the hydraulic oil filter light icon on the LCD and the charge filter will be bypassed. Charge pressure oil is then routed to the traction pump. Charge pressure oil is also routed to the CHG port of the brake release valve. Traction Drive Circuit When the traction pedal is moved to the forward position, the EDC (electronic displacement control) is moved to the forward position. Charge pressure oil is supplied to the 40-mesh screen. Oil is then routed to the EDC and the control sleeve. With the EDC in the forward position, oil flows through the EDC to the control sleeve. Oil pressure from the EDC pilot lines is greater on the forward side of the control sleeve and the control sleeve shifts to the forward position. Oil is then routed to the forward side of the servo piston and the swashplate is moved to the forward direction. Oil at operating pressure is routed against the check valve and forward relief valve, and exits the traction pump at port A. Oil is then routed in parallel to the front wheel motors, driving the motors in the forward direction. Oil exiting the left front wheel motor enters port LF of the 4WD valve and is routed against the 400 psi (8 bar) RF relief valve, against the 400 psi (8 bar) LF relief valve and pilot line of the LF relief valve, against the RRF check valve, and to the right rear wheel motor. Oil exiting the right rear wheel motor flows against the RRF check valve, against the hot oil shuttle, exits the 4WD valve at the REV port, and is returned to the traction pump to replenish the intake side of the pump. Oil exiting the right front wheel motor enters port RF of the 4WD valve and is routed against the 400 psi (8 bar) RF relief valve and pilot line of the RF relief valve, against the 400 psi (8 bar) LF relief valve, against the pilot line of the hot oil shuttle, against the LRF check valve, and to the left rear wheel motor. Oil exiting the left rear wheel motor flows against the LRF check valve, against the hot oil shuttle, exits the 4WD valve at the REV port, and is returned to the traction pump to replenish the intake side of the pump. Park Brake Circuit The front wheel motors are equipped with multi-disk wet brakes. The brakes are spring-applied, and released with pressurized oil controlled by the brake solenoid valve and the brake release valve. Operating Mode With the brake release valve in the normal operating position, the park brake switch off, and traction pedal in the forward position, charge pressure oil flows through the brake solenoid valve, through the brake release valve, and to the brake cylinders in the front wheel motors, releasing the brakes. With the brake release valve in the normal operating position and the park brake switch on, oil from the brake cylinders is released through the brake release valve, through the brake solenoid valve, and to the hydraulic tank, engaging the brakes. Towing Mode The park brake circuit is equipped with a lever-operated brake release valve to allow the release of the brakes with a dead engine for towing purposes. When the brake release lever is moved to the released position, the oil passage in the brake release valve is opened to the steering cylinder. This oil pathway provides a means to release the brakes with the engine off by turning the steering wheel, routing oil from the steering circuit to the brake cylinders to release the brakes. Hot Oil Shuttle The hot oil shuttle is used to remove hot oil from the closed-loop traction drive circuit when moving forward. Oil lost due to venting through the hot oil shuttle is replenished by return oil from the rear wheel motors. When driving forward, operating pressure oil is routed to the pilot line of the hot oil shuttle, shifting the valve spool and opening the valve. Hot oil from the rear wheel motors flows through the hot oil shuttle, through the 0.0 in. (.3 mm) orifice, and is routed back to the hydraulic oil tank Rev B

15 Circuit Relief The forward 4WD circuit is protected by the forward relief valve. For machines with serial numbers ending 6 through 499, the relief valve will open if the pressure rises to 36 psi (0 bar), allowing oil to dump to the return (low pressure) side of the circuit. For machines with serial numbers ending 00 and up, the relief valve will open if the pressure rises to 430 psi (300 bar), allowing oil to dump to the return (low pressure) side of the circuit. 446-Rev B -

16 Traction Circuit Forward Schematic (4WD Models) See Figures -4 and -. REV Test Port M B 30 ±0 rpm.8 ci Check Reverse Relief 36 psi 0.0 ci Gear Pump 0.0 ci 0.0 ci STRG Test Port Tow Check Forward Relief (See Note) 3 M M in in. Traction Pump A 3 4 Screen 40 Mesh L Control Sleeve Charge Pressure Relief 3 psi L FOW Test Port M M3 0 Micron Filter psi Switch Charge Filter 6 EDC psi Crack Bypass Micron Filter 9 psi Crack Bypass Return Filter Tank Fill Cap Assembly Oil Cooler psi Crack Bypass Suction Screen 00 Mesh 0 Micron Filter Hydraulic Tank Operating Pressure Oil Charge Pressure Oil Metered Oil Inlet or Drain Oil Return Oil Return Oil to Steering Unit (Port P) 4 Charge Pressure Oil to Rear Reel (Port P) 7 Return Oil from Rear Wheel Motors Case Drains, 4WD (DRN Port), and Reel Motors Case Drains Charge Pressure Oil to 4WD (REV Port) Return Oil to Front Reel (Port P) 8 Return Oil from Front Reel (Port T) 3 Operating Pressure Oil to Front Axle Motors Note: Forward relief valve pressure is 36 psi for machines with serial numbers ending 6 through 499. Forward relief valve pressure is 430 psi for machines with serial numbers ending 00 and up. 6 Charge Pressure Oil from Rear Reel (Port T) 9 Charge Pressure Oil to Brake Release (CHG Port) Figure -4 TN Rev B

17 Traction Circuit Forward Schematic (4WD Models), Continued Reverse Left Front Wheel Motor Right Front Wheel Motor (See Note) Brake Cylinder Brake Cylinder (See Note) RF REV LF RF Relief 400 psi 3 4 Forward 4WD LF Relief 400 Hot Oil Shuttle DRN 6 RRR 0.0 in. Right Rear Wheel Motor RRF RRF Check LRF Check.90 ci.90 ci LRF LRR Left Rear Wheel Motor 7 9 DRN Relief 30 psi BR Brake Release A B 0 Check ST Solenoid Backlap CHG Brake Solenoid Rear Reel Test Port G Rear Reel P T Operating Pressure Oil Charge Pressure Oil Metered Oil Inlet or Drain Oil Charge Pressure Oil from Traction Pump (Port B) 3 Operating Pressure Oil from Traction Pump (Port A) 4 Charge Pressure Oil from Section of Gear Pump Note: Front wheel motor displacement is 9.3 ci for machines with serial numbers ending 6 through 499. Front wheel motor displacement is 7.09 ci for machines with serial numbers ending 00 and up. 6 Charge Pressure Oil to Charge Filter 0 Case Drain Oil from Reel Motors 7 Return Oil to Hydraulic Tank Return Oil from Rod End of Steering Cylinder 9 Charge Pressure Oil from Charge Filter Figure - TN Rev B -7

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19 Traction Circuit Reverse Schematic and Theory of Operation (4WD Models) System Conditions: Engine running Park brake switch in the off position (park brake disengaged) Traction pedal in the reverse position Charge Pressure Circuit The traction pump and gear pump are both driven by the engine. Section of the gear pump provides charge pressure oil for the rear reel circuit and the traction pump. Hydraulic oil is drawn from the hydraulic tank through a 00-mesh screen, and enters the gear pump, supplying oil to all three pump sections. Oil from section of the gear pump is routed through the rear reel valve to the charge filter. The charge filter uses a 0-micron filter to remove debris from the oil. In the event of the charge filter becoming plugged, a psi (.7 bar) pressure switch will activate the hydraulic oil filter light icon on the LCD and the charge filter will be bypassed. Charge pressure oil is then routed to the traction pump. Charge pressure oil is also routed to the CHG port of the brake release valve. Traction Drive Circuit When the traction pedal is moved to the reverse position, the EDC (electronic displacement control) is moved to the reverse position. Charge pressure oil is supplied to the 40-mesh screen. Oil is then routed to the EDC and the control sleeve. With the EDC in the reverse position, oil flows through the EDC to the control sleeve. Oil pressure from the EDC pilot lines is greater on the reverse side of the control sleeve and the control sleeve shifts to the reverse position. Oil is then routed to the reverse side of the servo piston and the swashplate is moved to the reverse direction. Oil at operating pressure is routed against the check valve and 36 psi (0 bar) reverse relief valve, and exits the traction pump at port B. Operating pressure oil from port B of the traction pump enters the 4WD valve at the REV port, is routed against the hot oil shuttle, and is then routed in parallel to the RRF and LRF check valves, and in parallel to the rear wheel motors. Oil flows through the RRF check valve, against the right rear wheel motor, against the against the LF relief valve and pilot of the LF relief valve, against the RF relief valve, and exits the 4WD valve at port LF. Oil is then routed to the left front wheel motor, driving the motor in the reverse direction. Oil also flows through the LRF check valve, against the left rear wheel motor, against the pilot of the hot oil shuttle, against the LF relief valve, against the RF relief valve and pilot of the RF relief valve, and exits the 4WD valve at port RF. Oil is then routed to the right front wheel motor; driving the motor in the reverse direction. Since pressure is equal on both sides of the rear wheel motors, the rear wheels are free to rotate but do not contribute to traction in the reverse direction. Oil exiting the front wheel motors is returned to the traction pump to replenish the intake side of the pump. Park Brake Circuit The front wheel motors are equipped with multi-disk wet brakes. The brakes are spring-applied, and released with pressurized oil controlled by the brake solenoid valve and the brake release valve. Operating Mode With the brake release valve in the normal operating position, the park brake switch off, and traction pedal in the reverse position, charge pressure oil flows through the brake solenoid valve, through the brake release valve, and to the brake cylinders in the front wheel motors, releasing the brakes. With the brake release valve in the normal operating position and the park brake switch on, oil from the brake cylinders is released through the brake release valve, through the brake solenoid valve, and to the hydraulic tank, engaging the brakes. Towing Mode The park brake circuit is equipped with a lever-operated brake release valve to allow the release of the brakes with a dead engine for towing purposes. When the brake release lever is moved to the released position, the oil passage in the brake release valve is opened to the steering cylinder. This oil pathway provides a means to release the brakes with the engine off by turning the steering wheel, routing oil from the steering circuit to the brake cylinders to release the brakes. Circuit Relief The reverse side of the traction circuit is protected by the reverse relief valve. The relief valve will open if the pressure rises to 36 psi (0 bar), allowing oil to dump to the return (low pressure) side of the circuit. 446-Rev B -9

20 Traction Circuit Reverse Schematic (4WD Models) See Figures -6 and -7. REV Test Port M B 30 ±0 rpm.8 ci Check Reverse Relief 36 psi 0.0 ci Gear Pump 0.0 ci 0.0 ci STRG Test Port Tow Check Forward Relief (See Note) 3 M M in in. Traction Pump A 3 4 Screen 40 Mesh L Control Sleeve Charge Pressure Relief 3 psi L FOW Test Port M M3 0 Micron Filter psi Switch Charge Filter 6 EDC psi Crack Bypass Micron Filter 9 psi Crack Bypass Return Filter Tank Fill Cap Assembly Oil Cooler psi Crack Bypass Suction Screen 00 Mesh 0 Micron Filter Hydraulic Tank Operating Pressure Oil Charge Pressure Oil Metered Oil Inlet or Drain Oil Return Oil Return Oil to Steering Unit (Port P) 4 Charge Pressure Oil to Rear Reel (Port P) 7 Return Oil from Rear Wheel Motors Case Drains, 4WD (DRN Port), and Reel Motors Case Drains Operating Pressure Oil to 4WD (REV Port) Return Oil to Front Reel (Port P) 8 Return Oil from Front Reel (Port T) 3 Charge Pressure Oil to Front Axle Motors Note: Forward relief valve pressure is 36 psi for machines with serial numbers ending 6 through 499. Forward relief valve pressure is 430 psi for machines with serial numbers ending 00 and up. 6 Charge Pressure Oil from Rear Reel (Port T) 9 Charge Pressure Oil to Brake Release (CHG Port) Figure -6 TN Rev B

21 Traction Circuit Reverse Schematic (4WD Models), Continued Reverse Left Front Wheel Motor Right Front Wheel Motor (See Note) Brake Cylinder Brake Cylinder (See Note) RF REV LF RF Relief 400 psi 3 4 Forward 4WD LF Relief 400 Hot Oil Shuttle DRN 6 RRR 0.0 in. Right Rear Wheel Motor RRF RRF Check LRF Check.90 ci.90 ci LRF LRR Left Rear Wheel Motor 7 9 DRN Relief 30 psi BR Brake Release A B 0 Check ST Solenoid Backlap CHG Brake Solenoid Rear Reel Test Port G Rear Reel P T Operating Pressure Oil Charge Pressure Oil Inlet or Drain Oil Operating Pressure Oil from Traction Pump (Port B) 3 Charge Pressure Oil from Traction Pump (Port A) 4 Charge Pressure Oil from Section of Gear Pump Note: Front wheel motor displacement is 9.3 ci for machines with serial numbers ending 6 through 499. Front wheel motor displacement is 7.09 ci for machines with serial numbers ending 00 and up. 6 Charge Pressure Oil to Charge Filter 0 Case Drain Oil from Reel Motors 7 Return Oil to Hydraulic Tank Return Oil from Rod End of Steering Cylinder 9 Charge Pressure Oil from Charge Filter Figure -7 TN Rev B -

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23 Traction Circuit Neutral Schematic and Theory of Operation (WD Models) System Conditions: Engine running Park brake switch in the on position (park brake engaged) Traction pedal in the neutral position Charge Pressure Circuit The traction pump and gear pump are both driven by the engine. Section of the gear pump provides charge pressure oil for the rear reel circuit and the traction pump. Hydraulic oil is drawn from the hydraulic tank through a 00-mesh screen, and enters the gear pump, supplying oil to all three pump sections. Oil from section of the gear pump is routed through the rear reel valve to the charge filter. The charge filter uses a 0-micron filter to remove debris from the oil. In the event of the charge filter becoming plugged, a psi (.7 bar) pressure switch will activate the hydraulic oil filter light icon on the LCD and the charge filter will be bypassed. Charge pressure oil is then routed to the traction pump. Charge pressure oil is also routed to the CHG port of the brake release valve. Traction Pump Circuit With the traction pedal in the neutral position, the EDC (electronic displacement control) valve is in the neutral position and oil pressure in both pilot lines to the control sleeve is equal. Since pressure is equal on both sides of the control sleeve, the control sleeve is centered in the neutral position. Oil is not supplied to the servo pistons and no movement of the swashplate occurs. The charge oil is supplied to the closed-loop traction circuit via the check valves and exits the traction pump at ports A and B. The oil is then routed in parallel to the front wheel motors. Since pressure is equal on both sides of the front wheel motors, no movement occurs. With the closed-loop circuit charged with oil, the 3 psi ( bar) charge pressure relief valve will open and vent excess oil to the hydraulic tank. Hydraulic oil is used to lubricate the internal components of pumps and motors. This oil is returned via the case drain lines back to the hydraulic tank. Park Brake Circuit The front wheel motors are equipped with multi-disk wet brakes. The brakes are spring-applied, and released with pressurized oil controlled by the brake solenoid valve and the brake release valve. Towing Mode The park brake circuit is equipped with a lever-operated brake release valve to allow the release of the brakes with a dead engine for towing purposes. When the brake release lever is moved to the released position, the oil passage in the brake release valve is opened to the steering cylinder. This oil pathway provides a means to release the brakes with the engine off by turning the steering wheel, routing oil from the steering circuit to the brake cylinders to release the brakes. 446-Rev B -3

24 Traction Circuit Neutral Schematic (WD Models) See Figures -8 and -9. REV Test Port M B 30 ±0 rpm.8 ci Check Reverse Relief 36 psi 0.0 ci Gear Pump 0.0 ci 0.0 ci STRG Test Port Tow Check Forward Relief (See Note) 3 M M in in. Traction Pump A 3 4 Screen 40 Mesh L Control Sleeve Charge Pressure Relief 3 psi L FOW Test Port M M3 0 Micron Filter psi Switch Charge Filter 6 EDC psi Crack Bypass Micron Filter 9 psi Crack Bypass Return Filter Tank Fill Cap Assembly Oil Cooler psi Crack Bypass Suction Screen 00 Mesh 0 Micron Filter Hydraulic Tank Charge Pressure Oil Metered Oil Inlet or Drain Oil Return Oil Return Oil to Steering Unit (Port P) 4 Charge Pressure Oil to Rear Reel (Port P) 7 Return Oil from Rear Wheel Motors Case Drains, 4WD (DRN Port), and Reel Motors Case Drains Charge Pressure Oil to 4WD (REV Port) Return Oil to Front Reel (Port P) 8 Return Oil from Front Reel (Port T) 3 Charge Pressure Oil to Front Axle Motors Note: Forward relief valve pressure is 36 psi for machines with serial numbers ending 6 through 499. Forward relief valve pressure is 430 psi for machines with serial numbers ending 00 and up. 6 Charge Pressure Oil from Rear Reel (Port T) Figure -8 9 Charge Pressure Oil to Brake Release (CHG Port) TN Rev B

25 Traction Circuit Neutral Schematic (WD Models), Continued Reverse Left Front Wheel Motor Right Front Wheel Motor (See Note) Brake Cylinder Brake Cylinder (See Note) 3 4 Forward DRN Relief 30 psi BR Brake Release A B 0 Check ST Solenoid Backlap CHG Brake Solenoid Rear Reel Test Port G Rear Reel P T Charge Pressure Oil Charge Pressure Oil from Traction Pump (Port B) 3 Charge Pressure Oil from Traction Pump (Port A) 4 Charge Pressure Oil from Section of Gear Pump Note: Front wheel motor displacement is 9.3 ci for machines with serial numbers ending 6 through 499. Front wheel motor displacement is 7.09 ci for machines with serial numbers ending 00 and up. 6 Charge Pressure Oil to Charge Filter 0 Case Drain Oil from Reel Motors 7 Return Oil to Hydraulic Tank Return Oil from Rod End of Steering Cylinder 9 Charge Pressure Oil from Charge Filter Figure -9 TN Rev B -

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27 Traction Circuit Forward Schematic and Theory of Operation (WD Models) System Conditions: Engine running Park brake switch in the off position (park brake disengaged) Traction pedal in the forward position Charge Pressure Circuit The traction pump and gear pump are both driven by the engine. Section of the gear pump provides charge pressure oil for the rear reel circuit and the traction pump. Hydraulic oil is drawn from the hydraulic tank through a 00-mesh screen, and enters the gear pump, supplying oil to all three pump sections. Oil from section of the gear pump is routed through the rear reel valve to the charge filter. The charge filter uses a 0-micron filter to remove debris from the oil. In the event of the charge filter becoming plugged, a psi (.7 bar) pressure switch will activate the hydraulic oil filter light icon on the LCD and the charge filter will be bypassed. Charge pressure oil is then routed to the traction pump. Charge pressure oil is also routed to the CHG port of the brake release valve. Traction Drive Circuit When the traction pedal is moved to the forward position, the EDC (electronic displacement control) is moved to the forward position. Charge pressure oil is supplied to the 40-mesh screen. Oil is then routed to the EDC and the control sleeve. With the EDC in the forward position, oil flows through the EDC to the control sleeve. Oil pressure from the EDC pilot lines is greater on the forward side of the control sleeve and the control sleeve shifts to the forward position. Oil is then routed to the forward side of the servo piston and the swashplate is moved to the forward direction. Oil at operating pressure is routed against the check valve and forward relief valve, and exits the traction pump at port A. Oil is then routed to the front wheel motors, driving the motors in the forward direction. Oil exiting the front wheel motors is returned to the traction pump to replenish the intake side of the pump. Park Brake Circuit The front wheel motors are equipped with multi-disk wet brakes. The brakes are spring-applied, and released with pressurized oil controlled by the brake solenoid valve and the brake release valve. Operating Mode With the brake release valve in the normal operating position, the park brake switch off, and traction pedal in the forward position, charge pressure oil flows through the brake solenoid valve, through the brake release valve, and to the brake cylinders in the front wheel motors, releasing the brakes. With the brake release valve in the normal operating position and the park brake switch on, oil from the brake cylinders is released through the brake release valve, through the brake solenoid valve, and to the hydraulic tank, engaging the brakes. Towing Mode The park brake circuit is equipped with a lever-operated brake release valve to allow the release of the brakes with a dead engine for towing purposes. When the brake release lever is moved to the released position, the oil passage in the brake release valve is opened to the steering cylinder. This oil pathway provides a means to release the brakes with the engine off by turning the steering wheel, routing oil from the steering circuit to the brake cylinders to release the brakes. Circuit Relief The forward side of the traction circuit is protected by the forward relief valve. For machines with serial numbers ending 6 through 499, the relief valve will open if the pressure rises to 36 psi (0 bar), allowing oil to dump to the return (low pressure) side of the circuit. For machines with serial numbers ending 00 and up, the relief valve will open if the pressure rises to 430 psi (300 bar), allowing oil to dump to the return (low pressure) side of the circuit. 446-Rev B -7

28 Traction Circuit Forward Schematic (WD Models) See Figures -0 and -. REV Test Port M B 30 ±0 rpm.8 ci Check Reverse Relief 36 psi 0.0 ci Gear Pump 0.0 ci 0.0 ci STRG Test Port Tow Check Forward Relief (See Note) 3 M M in in. Traction Pump A 3 4 Screen 40 Mesh L Control Sleeve Charge Pressure Relief 3 psi L FOW Test Port M M3 0 Micron Filter psi Switch Charge Filter 6 EDC psi Crack Bypass Micron Filter 9 psi Crack Bypass Return Filter Tank Fill Cap Assembly Oil Cooler psi Crack Bypass Suction Screen 00 Mesh 0 Micron Filter Hydraulic Tank Operating Pressure Oil Charge Pressure Oil Metered Oil Inlet or Drain Oil Return Oil Return Oil to Steering Unit (Port P) 4 Charge Pressure Oil to Rear Reel (Port P) 7 Return Oil from Rear Wheel Motors Case Drains, 4WD (DRN Port), and Reel Motors Case Drains Charge Pressure Oil to 4WD (REV Port) Return Oil to Front Reel (Port P) 8 Return Oil from Front Reel (Port T) 3 Operating Pressure Oil to Front Axle Motors Note: Forward relief valve pressure is 36 psi for machines with serial numbers ending 6 through 499. Forward relief valve pressure is 430 psi for machines with serial numbers ending 00 and up. 6 Charge Pressure Oil from Rear Reel (Port T) 9 Charge Pressure Oil to Brake Release (CHG Port) Figure -0 TN Rev B

29 Traction Circuit Forward Schematic (WD Models), Continued Reverse Left Front Wheel Motor Right Front Wheel Motor (See Note) Brake Cylinder Brake Cylinder (See Note) 3 4 Forward DRN Relief 30 psi BR Brake Release A B 0 Check ST Solenoid Backlap CHG Brake Solenoid Rear Reel Test Port G Rear Reel P T Operating Pressure Oil Charge Pressure Oil Charge Pressure Oil from Traction Pump (Port B) 3 Operating Pressure Oil from Traction Pump (Port A) 4 Charge Pressure Oil from Section of Gear Pump Note: Front wheel motor displacement is 9.3 ci for machines with serial numbers ending 6 through 499. Front wheel motor displacement is 7.09 ci for machines with serial numbers ending 00 and up. 6 Charge Pressure Oil to Charge Filter 0 Case Drain Oil from Reel Motors 7 Return Oil to Hydraulic Tank Return Oil from Rod End of Steering Cylinder 9 Charge Pressure Oil from Charge Filter Figure - TN Rev B -9

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31 Traction Circuit Reverse Schematic and Theory of Operation (WD Models) System Conditions: Engine running Park brake switch in the off position (park brake disengaged) Traction pedal in the reverse position Charge Pressure Circuit The traction pump and gear pump are both driven by the engine. Section of the gear pump provides charge pressure oil for the rear reel circuit and the traction pump. Hydraulic oil is drawn from the hydraulic tank through a 00-mesh screen, and enters the gear pump, supplying oil to all three pump sections. Oil from section of the gear pump is routed through the rear reel valve to the charge filter. The charge filter uses a 0-micron filter to remove debris from the oil. In the event of the charge filter becoming plugged, a psi (.7 bar) pressure switch will activate the hydraulic oil filter light icon on the LCD and the charge filter will be bypassed. Charge pressure oil is then routed to the traction pump. Charge pressure oil is also routed to the CHG port of the brake release valve. Traction Drive Circuit When the traction pedal is moved to the reverse position, the EDC (electronic displacement control) is moved to the reverse position. Charge pressure oil is supplied to the 40-mesh screen. Oil is then routed to the EDC and the control sleeve. With the EDC in the reverse position, oil flows through the EDC to the control sleeve. Oil pressure from the EDC pilot lines is greater on the reverse side of the control sleeve and the control sleeve shifts to the reverse position. Oil is then routed to the reverse side of the servo piston and the swashplate is moved to the reverse direction. Oil at operating pressure is routed against the check valve and 36 psi (0 bar) reverse relief valve, and exits the traction pump at port B. Oil is then routed to the front wheel motors, driving the motors in the reverse direction. Oil exiting the front wheel motors is returned to the traction pump to replenish the intake side of the pump. Park Brake Circuit The front wheel motors are equipped with multi-disk wet brakes. The brakes are spring-applied, and released with pressurized oil controlled by the brake solenoid valve and the brake release valve. Operating Mode With the brake release valve in the normal operating position, the park brake switch off, and traction pedal in the reverse position, charge pressure oil flows through the brake solenoid valve, through the brake release valve, and to the brake cylinders in the front wheel motors, releasing the brakes. With the brake release valve in the normal operating position and the park brake switch on, oil from the brake cylinders is released through the brake release valve, through the brake solenoid valve, and to the hydraulic tank, engaging the brakes. Towing Mode The park brake circuit is equipped with a lever-operated brake release valve to allow the release of the brakes with a dead engine for towing purposes. When the brake release lever is moved to the released position, the oil passage in the brake release valve is opened to the steering cylinder. This oil pathway provides a means to release the brakes with the engine off by turning the steering wheel, routing oil from the steering circuit to the brake cylinders to release the brakes. Circuit Relief The reverse side of the traction circuit is protected by the reverse relief valve. The relief valve will open if the pressure rises to 36 psi (0 bar), allowing oil to dump to the return (low pressure) side of the circuit. 446-Rev B -3

32 Traction Circuit Reverse Schematic (WD Models) See Figures - and -3. REV Test Port M B 30 ±0 rpm.8 ci Check Reverse Relief 36 psi 0.0 ci Gear Pump 0.0 ci 0.0 ci STRG Test Port Tow Check Forward Relief (See Note) 3 M M in in. Traction Pump A 3 4 Screen 40 Mesh L Control Sleeve Charge Pressure Relief 3 psi L FOW Test Port M M3 0 Micron Filter psi Switch Charge Filter 6 EDC psi Crack Bypass Micron Filter 9 psi Crack Bypass Return Filter Tank Fill Cap Assembly Oil Cooler psi Crack Bypass Suction Screen 00 Mesh 0 Micron Filter Hydraulic Tank Operating Pressure Oil Charge Pressure Oil Metered Oil Inlet or Drain Oil Return Oil Return Oil to Steering Unit (Port P) 4 Charge Pressure Oil to Rear Reel (Port P) 7 Return Oil from Rear Wheel Motors Case Drains, 4WD (DRN Port), and Reel Motors Case Drains Operating Pressure Oil to 4WD (REV Port) Return Oil to Front Reel (Port P) 8 Return Oil from Front Reel (Port T) 3 Charge Pressure Oil to Front Axle Motors Note: Forward relief valve pressure is 36 psi for machines with serial numbers ending 6 through 499. Forward relief valve pressure is 430 psi for machines with serial numbers ending 00 and up. 6 Charge Pressure Oil from Rear Reel (Port T) 9 Charge Pressure Oil to Brake Release (CHG Port) Figure - TN Rev B

33 Traction Circuit Reverse Schematic (WD Models), Continued Reverse Left Front Wheel Motor Right Front Wheel Motor (See Note) Brake Cylinder Brake Cylinder (See Note) 3 4 Forward DRN Relief 30 psi BR Brake Release A B 0 Check ST Solenoid Backlap CHG Brake Solenoid Rear Reel Test Port G Rear Reel P T Operating Pressure Oil Charge Pressure Oil Operating Pressure Oil from Traction Pump (Port B) 3 Charge Pressure Oil from Traction Pump (Port A) 4 Charge Pressure Oil from Section of Gear Pump Note: Front wheel motor displacement is 9.3 ci for machines with serial numbers ending 6 through 499. Front wheel motor displacement is 7.09 ci for machines with serial numbers ending 00 and up. 6 Charge Pressure Oil to Charge Filter 0 Case Drain Oil from Reel Motors 7 Return Oil to Hydraulic Tank Return Oil from Rod End of Steering Cylinder 9 Charge Pressure Oil from Charge Filter Figure -3 TN Rev B -33

34 Troubleshooting Mower Will Not Move Forward or Reverse Probable Cause Remedy Hydraulic oil not at correct level in reservoir. Tow valve open. Fill reservoir to correct level. (Refer to Parts and Maintenance Manual for correct oil specifications.) Close tow valve. (Refer to Safety and Operation Manual. ) Low charge pressure. Test charge pressure relief valve. (See Charge Pressure Test on page -44.) Repair or replace charge pressure relief valve or rear cutting units circuit components as needed. Front wheel motor worn or damaged. Test motor. (See Front Wheel Motors Tests on page -.) Repair or replace motor as needed. (See Front Wheel Motor (Earlier Machines) on page -7 or Front Wheel Motor (Later Machines) on page -8.) Rear wheel motor worn or damaged. Test motor. (See Rear Wheel Motors Tests on page -7.) Repair or replace motor as needed. (See Rear Wheel Motor on page -96.) System relief valves worn or damaged. Test pump. (See Traction System Test on page -4.) Repair or replace system relief valves as needed. (See Traction Pump on page -6.) Traction pump worn or damaged. Test pump. (See Traction System Test on page -4.) Repair or replace pump as needed. (See Traction Pump on page -6.) Damaged traction pedal position sensor. Substitute traction pedal position sensor with a known good traction pedal position sensor. Faulty traction solenoid. Test traction solenoid. (See Traction Solenoid Test on page 4-7.) Repair or replace EDC as needed. (See Traction Pump on page -6.) Faulty EDC. Substitute EDC with a known good EDC. Mower Will Not Reach Full Speed Probable Cause Remedy Hydraulic oil not at correct level in reservoir. Fill reservoir to correct level. (Refer to Parts and Maintenance Manual for correct oil specifications.) Tow valve open. Close tow valve. (Refer to Safety and Operation Manual. ) Air in hydraulic system (air bubbles in hydraulic oil). Check suction line for air leaks. Repair as needed. Operate various hydraulic systems until hydraulic system is free of air. Low charge pressure. Test charge pressure relief valve. (See Charge Pressure Test on page -44.) Repair or replace charge pressure relief valve or rear cutting units circuit components as needed. System relief valves worn or damaged. Test pump. (See Traction System Test on page -4.) Repair or replace system relief valves as needed. (See Traction Pump on page -6.) Traction pump worn or damaged. Test pump. (See Traction System Test on page -4.) Repair or replace pump as needed. (See Traction Pump on page -6.) Front wheel motor worn or damaged. Test motor. (See Front Wheel Motors Tests on page -.) Repair or replace motor as needed. (See Front Wheel Motor (Earlier Machines) on page -7 or Front Wheel Motor (Later Machines) on page -8.) Rear wheel motor worn or damaged. Test motor. (See Rear Wheel Motors Tests on page -7.) Repair or replace motor as needed. (See Rear Wheel Motor on page -96.) Engine rpm low. Verify and adjust engine rpm. (Refer to the engine manufacturer s manual for further instructions.) Rev B

35 Mower Moves When Traction Pedal Is in Neutral Probable Cause Traction pump neutral not properly adjusted. Faulty EDC. Remedy Adjust traction pump neutral. (See Neutral Adjustments on page -36.) Substitute EDC with a known good EDC. Hydrostatic System Operating Hot Probable Cause Remedy Hydraulic oil not at correct level in reservoir. Tow valve open. Oil cooler has dirt or debris in fins. Excessive Traction Pump Noise Fill reservoir to correct level. (Refer to Parts and Maintenance Manual for correct oil specifications.) Close tow valve. (Refer to Safety and Operation Manual. ) Clean oil cooler fins of dirt and debris. Faulty hot oil shuttle. Inspect and repair. (See 4WD on page -69.) Slippage in pump or motor. Faulty charge pressure relief valve. Perform instrument tests. (See Instrument Test Procedures on page -43.) Test charge pressure relief valve. (See Charge Pressure Test on page -44.) Repair or replace charge pressure relief valve as needed. (See Traction Pump on page -6.) Probable Cause Hydraulic oil not at correct level in reservoir. Hydraulic oil cold. Air in hydraulic system (air bubbles in hydraulic oil). Traction pump worn or damaged. Remedy Fill reservoir to correct level. (Refer to Parts and Maintenance Manual for correct oil specifications.) Warm hydraulic oil to operating temperature. Check suction line for air leaks. Repair as needed. Operate various hydraulic systems until hydraulic system is free of air. Test pump. (See Traction System Test on page -4.) Repair or replace pump as needed. (See Traction Pump on page -6.) 446-Rev B -3

36 Tests and Adjustments Neutral Adjustments Swashplate Neutral Adjustment See Figures -4 and Remove floorboard. (See Floorboard on page 9-4.) IMPORTANT This adjustment works together with the EDC neutral adjustment.! WARNING The hydraulic system is under pressure, and the oil will be hot. Always relieve pressure in the hydraulic system before performing service. Failure to follow appropriate safety precautions may result in death or serious injury. 4 3 Required Tools and Materials -4 ORFS Test Hose 4000 psi (76 bar). Park the mower safely. (See Park Mower Safely on page -6.)! WARNING Prevent personal injury. Use properly rated lifting devices. Always be sure load is balanced before lifting. Support the machine properly using jackstands. Figure -4 TN300 Lock nut (3), neutral adjustment screw (4), and port () are located beneath the traction solenoid (). 9. Shunt the servo piston by connecting test hose to ports ( and ). IMPORTANT It is important to lift and support the machine or the machine will move.. Lift and support the machine so that all four wheels are off the ground and support with jackstands. 3. Start engine and run at full throttle (30 rpm ± 0). 4. Release park brake (park brake switch in the off position).. Operate hydraulic system until oil temperature is at 0 0 F (49 6 C). 6. Stop engine and engage park brake (park brake switch in the on position). 7. Remove hydro cover. (See Hydro Cover on page 9-4.). 6 TN376 Figure - 0. Rotate brake release lever (6) to the up position.. Start engine and run at full throttle (30 rpm ± 0) Rev B

37 . Turn steering wheel to the right to hydraulically disengage the park brake. 3. Hold neutral adjustment screw (4) and loosen lock nut (3). 4. Turn neutral adjustment screw until a front wheel begins to rotate. Note position of neutral adjustment screw.. Turn neutral adjustment screw in the opposite direction until a front wheel begins to rotate in the opposite direction. Note position of neutral adjustment screw. 6. Turn neutral adjustment screw halfway between the two positions. 7. Hold neutral adjustment screw (4) and tighten lock nut (3) to 7 lb-ft (36.6 N m). 8. Remove test hose from ports ( and ). 9. Proceed to EDC Neutral Adjustment. EDC Neutral Adjustment See Figures -6 and -7. IMPORTANT This adjustment works together with the swashplate neutral adjustment.! WARNING The hydraulic system is under pressure, and the oil will be hot. Always relieve pressure in the hydraulic system before performing service. Failure to follow appropriate safety precautions may result in death or serious injury. 6. Stop engine, engage park brake (park brake switch in the on position). Figure Rotate brake release lever () to the up position. 8. Start engine and run at full throttle (30 rpm ± 0). 9. Turn steering wheel to the right to hydraulically disengage the park brake. 3 TN376 Required Tools and Materials -4 ORFS Test Hose 4000 psi (76 bar). Park the mower safely. (See Park Mower Safely on page -6.). Before performing this adjustment, perform swashplate neutral adjustment leaving machine lifted and supported as outlined. (See Swashplate Neutral Adjustment on page -36.) 3. Start engine and run at full throttle (30 rpm ± 0). 4. Release park brake (park brake switch in the off position).. Operate hydraulic system until oil temperature is at 0 0 F (49 6 C). Figure -7 TN30 0. Hold neutral adjustment screw () and loosen lock nut (3). 446-Rev B -37

38 . Turn neutral adjustment screw until a front wheel begins to rotate. Note position of neutral adjustment screw.. Turn neutral adjustment screw in the opposite direction until a front wheel begins to rotate in the opposite direction. Note position of neutral adjustment screw. 3. Turn neutral adjustment screw halfway between the two positions. 4. Hold neutral adjustment screw () and tighten lock nut (3) to 7 lb-ft (36.6 N m.. Stop engine, engage park brake (park brake switch in the on position). 6. Disconnect and remove test equipment. Install all fittings as noted prior to removal Rev B

39 Field Test Procedures When a hydraulic system failure occurs, some simple effective tests can be performed prior to using a test instrument. The results of these tests can lead you to the suspected component failure. More extensive test procedures, using test instruments, are presented later in this section. (See Instrument Test Procedures on page -43.) Preliminary Checks Perform the following checks prior to beginning any tests.. Check the hydraulic oil reservoir for proper fluid level, the presence of air or water, and unusual odor.. Check all hoses, tubes, and fittings for leaks. Tighten as needed. 3. Eliminate all mechanical issues prior to starting hydraulic tests. Traction System Test See Figure -8. Be sure tow valve is closed before beginning traction system test.. Operate hydraulic system until oil temperature is at 0 0 F (49 6 C). IMPORTANT! WARNING Prevent personal injury. Use properly rated lifting devices. Always be sure load is balanced before lifting. Support the machine properly using jackstands. 3. It is important to lift and support the rear of the machine or the machine will move. 4. Lift the machine so that rear wheels are off the ground and support with jackstands.. Release park brake (park brake switch in the off position), lower the cutting units, and move throttle lever to full throttle. Slowly push the traction pedal forward. Does the engine labor or stall? YES The traction pump is not faulty. NO A fault exists in the hydrostatic drive circuit, which includes the traction pump and wheel motors. Proceed to instrument test. (See Instrument Test Procedures on page -43.) Figure -8. Install wheel restraints () to both front wheels. TN Rev B -39

40 Wheel Motor Test The wheel motor case drain is used to return lubrication oil or bypassed hydraulic oil to the hydraulic tank.. Operate hydraulic system until oil temperature is at 0 0 F (49 6 C).. Stop the engine, engage park brake (park brake switch in the on position), and remove the ignition key. 3. Remove the case drain hose from the wheel motor. Immediately plug the hose. 4. Position a drain pan with a minimum capacity of gallon (3.8 L) near the wheel motor.. Install a separate hose on the case drain fitting and place the free end in the container. Secure the hose to prevent spills. S When testing rear wheel motor, put wheel restraints on the rear wheels, lift front of machine so that front wheels are off the ground and support with jackstands. When testing front wheel motor, put wheel restraints on the front wheels, lift rear of machine so that rear wheels are off the ground and support with jackstands. 6. Install wheel restraints. See Figure Lift and support the rear or front of the machine, depending on wheel being tested. 8. Start the engine, release park brake (park brake switch in the off position), and place the traction pedal in the forward position for seconds. 9. Stop the engine, engage park brake (park brake switch in the on position), and remove the ignition key. 0. Measure the amount of oil collected from the case drain. Amount x 4 = amount per minute. Is the oil measured less than gallon per minute? YES The motor is not faulty. Proceed to instrument test. (See Instrument Test Procedures on page -43.) Is the oil measured more than gallons per minute? NO The motor is faulty. Repair or replace as needed. (See Front Wheel Motor (Earlier Machines) on page -7, Front Wheel Motor (Later Machines) on page -8, or Rear Wheel Motor on page -96.) Brake System Test See Figures -9 through -. IMPORTANT! WARNING Prevent personal injury. Use properly rated lifting devices. Always be sure load is balanced before lifting. Support the machine properly using jackstands. It is important to lift and support the machine or the machine will move.. Raise and support all four wheels off the ground. Figure -9 Figure -0 TN3649. Connect test hose and pressure gauge () to rear reel test port G () of the rear reel valve. TN Rev B

41 Verify engine rpm is within specification (30 rpm ± 0) to ensure accurate hydraulic test results. 3. Start engine and run at full throttle (30 rpm ± 0). 4. Operate hydraulic system until oil temperature is at 0 0 F (49 6 C).. Observe charge pressure reading. Is charge pressure 3 ± 0% psi ( ± 0% bar)? YES Charge pressure relief valve is good. Proceed to step 6. NO A fault exists in the hydrostatic drive circuit, which includes the charge pressure relief valve. Proceed to instrument test. (See Instrument Test Procedures on page -43.) 6. Release park brake (park brake switch in the off position) and engage traction pedal in the forward position until brake releases. Observe charge pressure reading. Does charge pressure drop below 8 psi (0 bar)? NO The brake cylinder is not faulty. Stop the engine, remove ignition key. For machine serial numbers 6 499, proceed to step 6. For machine serial numbers 00 and up, replace front wheel motor, then proceed to step 9. (See Front Wheel Motor (Later Machines) on page -8.) YES The 30 psi relief valve in the brake release valve may be faulty. Inspect the 30 psi relief valve and repair or replace as necessary. See Brake Release on page -67, then proceed to step Retest brake system. Does charge pressure drop below 8 psi (0 bar)? NO The brake cylinder is not faulty. Stop the engine, remove ignition key. For machine serial numbers 6 499, proceed to step 6. For machine serial numbers 00 and up, replace front wheel motor, then proceed to step 9. (See Front Wheel Motor (Later Machines) on page -8.) YES The brake cylinders may be faulty. Stop the engine, remove ignition key, and proceed to step TN304 Figure -: Front Wheel Motor for Machines with Serial Numbers Ending 6 Through 499 TN4666 Figure -: Front Wheel Motor for Machines with Serial Numbers Ending 00 and Up 8. Remove the case drain hose (3) from each front wheel motor. Immediately plug the hoses. 9. Position a drain pan with a minimum capacity of gallon (3.8 L) near each front wheel motor. 0. Install a separate hose on the case drain fitting (4) of each front wheel motor and place the free end of each hose in the container. Secure hoses to prevent spills.. Start the engine, release park brake (park brake switch in the off position), and engage the traction pedal in the forward position until the brake releases.. Look for oil coming out of the case drain hose. 3. For machine serial numbers 6 499, proceed to step. 4. For machine serial numbers 00 and up, proceed to step Rev B -4

42 . Stop the engine and remove the ignition key. Was oil observed coming out of the case drain hose? NO The brake cylinder is not faulty. Proceed to step 6. YES The brake cylinder is faulty. Repair or replace front wheel motors as needed, then proceed to step 9. (See Front Wheel Motor (Earlier Machines) on page -7.) 6. Remove front wheels. (See Front Wheel (Earlier Machines) on page 9-8.) It is not necessary to remove the wheel motor from the machine to service the brake disks or stator rings. 7. Inspect, repair, or replace the brake disks and stator rings. See steps through of front wheel motor Disassembly and Inspection on page -7, then proceed to step Stop the engine and remove the ignition key. Was oil observed coming out of the case drain hose? NO The brake cylinder is not faulty. Replace front wheel motor, then proceed to step 9. (See Front Wheel Motor (Later Machines) on page -8.) YES The brake cylinder is faulty. Repair or replace front wheel motors as needed, then proceed to step 9. (See Front Wheel Motor (Later Machines) on page -8.) 9. Disconnect and remove test equipment. Install all hoses and fittings as noted prior to removal. 0. Install and connect all components as noted prior to test.. Check hydraulic oil level. Add oil as needed. (Refer to Parts and Maintenance Manual for correct oil specifications.). Start engine. Check hydraulic system for leaks. Repair as necessary Rev B

43 Instrument Test Procedures Instrument Test Overview The following tests are specifically designed to approach hydraulic testing on a system level. Each component within the system represents a portion of the total system leakage. An internal leakage percentage for each component will be calculated and recorded, enabling the technician to view the system performance issue more completely. The test results will help the technician to decide which repairs will best remedy the performance issue experienced by the operator. The internal leakage percentage ranges are as follows: 0 0% = Good 0% = Marginal % and Beyond = Bad Example: Traction System Performance Complaint The machine operator reports that the machine struggles to climb hills. The traction system is tested as outlined, and the calculated system leakage is 4%, a result that requires the testing of individual components. This result can also be interpreted as system efficiency of 76%. The components in question are as follows: traction pump, right front wheel motor, left front wheel motor, 4WD valve, left rear wheel motor, and right rear wheel motor. Following the procedures as outlined, test each individual component, then calculate and record leakage percentages. The results from this test reveal leakage of 3.3% in the traction pump, 0% in the right front wheel motor,.4% in the left front wheel motor,.% in the 4WD valve,.% in the left rear wheel motor, and 4.3% in the right rear wheel motor. Although all the components lend to the overall system leakage, only the right front wheel motor, which is at the extreme end of the marginal range, would be considered for repair or replacement. Formulas: System and Traction Pump No Load Flow Loaded Flow / No Load Flow x 00 = Leak Percentage Wheel Motor and 4WD Loaded Flow from previous component Loaded Flow from current component / Loaded Flow from previous component x 00 = Leak Percentage Calculations: System Test No Load Flow = gpm Loaded Flow =.4 gpm.4 / x 00 = Total System Leakage 4% Traction Pump Test No Load Flow = gpm Loaded Flow = 4. gpm 4. / x 00 = Traction Pump Leakage 3.3% Right Front Wheel Motor Test Loaded Flow from traction pump test = 4. gpm Loaded Flow from right front wheel motor test =.6 gpm 4..6 / 4. x 00 = Right Front Wheel Motor Leakage 0% Left Front Wheel Motor Test Loaded Flow from traction pump test = 4. gpm Loaded Flow from left front wheel test =4.3 gpm / 4. x 00 = Left Front Wheel Motor Leakage.4% 4WD Test Loaded Flow from left front wheel motor test = 4.3 gpm Loaded Flow from 4WD valve test = 4.0 gpm / 4.3 x 00 = 4WD Leakage.% Left Rear Wheel Motor Test Loaded Flow from 4WD valve test = 4.0 gpm Loaded Flow from left rear wheel motor test = 3.7 gpm / 4.0 x 00 = Left Rear Wheel Motor Leakage.% Right Rear Wheel Motor Test Loaded Flow from 4WD valve test = 4.0 gpm Loaded Flow from right rear wheel motor test = 3.4 gpm / 4.0 x 00 = Right Rear Wheel Motor Leakage 4.3% 446-Rev B -43

44 Charge Pressure Test See Figures -3 and -4.! WARNING The hydraulic system is under pressure, and the oil will be hot. Always relieve pressure in the hydraulic system before performing service. Failure to follow appropriate safety precautions may result in death or serious injury. Required Tools and Materials Pressure Gauge 00 psi (3 bar) Test Hose 00 psi (3 bar). Operate hydraulic system until oil temperature is at 0 0 F (49 6 C).. Park the mower safely. (See Park Mower Safely on page -6.) Figure -3 TN3649 Figure Connect test hose and pressure gauge () to rear reel test port G () of the rear reel valve. TN7 Verify engine rpm is within specification (30 rpm ± 0) to ensure accurate hydraulic test results. 4. Start engine and run at full throttle (30 rpm ± 0).. Record pressure reading. 6. Stop the engine. Is charge pressure 3 ± 0% psi ( ± 0% bar)? YES Charge pressure relief valve is good. Proceed to step 8. NO Inspect, repair, or replace 3 psi charge pressure relief valve. Proceed to step Retest charge pressure. Is charge pressure 3 ± 0% psi ( ± 0% bar)? YES Charge pressure relief valve is good. Proceed to step 8. NO Proceed to Rear Cutting Units Circuit Test on page Disconnect and remove test equipment. Install all hoses and fittings as noted prior to removal. 9. Install and connect all components as noted prior to test. 0. Check hydraulic oil level. Add oil as needed. (Refer to Parts and Maintenance Manual for correct oil specifications.). Start engine. Check hydraulic system for leaks. Repair as necessary Rev B

45 Traction System Test See Figures - through -3. IMPORTANT Performing this test will isolate the traction pump and front wheel motors from the rest of the hydrostatic system. This test works together with the traction pump tests, front wheel motors tests, 4WD valve test, and rear wheel motors tests to isolate a problem within the hydrostatic power train.! WARNING The hydraulic system is under pressure, and the oil will be hot. Always relieve pressure in the hydraulic system before performing service. Failure to follow appropriate safety precautions may result in death or serious injury. 3. Install wheel restraints () to both front wheels. IMPORTANT! WARNING Prevent personal injury. Use properly rated lifting devices. Always be sure load is balanced before lifting. Support the machine properly using jackstands. It is important to lift and support the rear of the machine or the machine will move. 4. Lift and support the machine so that the rear wheels are off the ground.. Close tow valve completely by turning clockwise. Required Tools and Materials Flow Meter - ORFS Test Hoses 000 psi (34 bar) -0 ORFS Test Hoses 000 psi (34 bar) Wheel Restraints 3 TN37. Park the mower safely. (See Park Mower Safely on page -6.) Figure -6. Bypass seat switch. 4 TN3834 Figure -7: Right Front Wheel Motor for Machines with Serial Numbers Ending 6 Through 499 Figure - TN Rev B -4

46 Figure -30 TN37 TN4668 Figure -8: Right Front Wheel Motor for Machines with Serial Numbers Ending 00 and Up 6. Disconnect hose (4) from fitting () on the front right wheel motor. 7. Connect test hose () of flow meter inlet to fitting (). 8. Connect test hose (3) of flow meter inlet to hose (4). 9. Disconnect hose (6) from fitting (7) on the 4WD valve. 0. Connect test hose (9) of flow meter outlet to fitting (7).. Connect hose (0) of flow meter outlet to hose (6). 6 7 Figure -9 TN3837 TN387 Figure -3: Traction System Test Front Wheel Motors Blocked Rev B

47 . Open flow meter valve (8) completely before starting engine. 3. Enter LCD maintenance mode and set MAX SPEED to 8 mph (3 km/h). (See LCD Maintenance Mode on page 4-44.) Verify engine rpm is within specification (30 rpm ± 0) to ensure accurate hydraulic test results. 4. Start engine and release park brake (park brake switch in the off position).. Depress traction pedal fully forward and set cruise control. 6. Verify flow is between 7 gpm (7 64 lpm). 7. Use the flow meter to warm the hydraulic oil. Turn the flow meter valve until a reading of 800 psi (4 bar) is reached. Warm oil to 0 0 F (49 6 C); open flow meter valve fully after operating temperature is reached. 8. After warming the hydraulic oil, verify cruise control is set to allow pump to produce 7 gpm (7 64 lpm) in the forward direction. 9. Read and record no load flow. 0. Slowly close flow meter valve until a pressure of 700 psi (86 bar) is reached. Read and record loaded flow.. Disengage cruise control switch, engage park brake (park brake switch in the on position), and stop the engine.. Calculate traction system leakage. (Step 9 Step 0 / Step 9 x 00 = Leakage Percentage) Is traction system leakage 0% or less? YES The traction system is good. Additional testing is required. Proceed to Front Wheel Motors Tests on page -. NO Proceed to next question. Is traction system leakage % to 0%? YES The traction system is marginal. Additional testing is required. Proceed to Traction Pump Tests on page -47. NO Proceed to next question. Is traction system leakage % or more? YES Test individual components in traction system for leakage. Proceed to Traction Pump Tests on page -47. Traction Pump Tests See Figures -3 through -38. IMPORTANT Performing this test will isolate the traction pump from the rest of the hydrostatic system. This test works together with the traction system test, front wheel motors tests, 4WD valve test, and rear wheel motors tests to isolate a problem within the hydrostatic power train.! WARNING The hydraulic system is under pressure, and the oil will be hot. Always relieve pressure in the hydraulic system before performing service. Failure to follow appropriate safety precautions may result in death or serious injury. Required Tools and Materials Flow Meter - ORFS Test Hoses 000 psi (34 bar) -0 ORFS Test Hoses 000 psi (34 bar) - ORFS and -0 ORFS Blocking Disks. Park the mower safely. (See Park Mower Safely on page -6.). Before performing this test, perform traction system test leaving rear of mower lifted and supported, and flow meter and front wheel restraints connected as outlined. (See Traction System Test on page -4.) 446-Rev B -47

48 TN3834 Figure -3: Right Front Wheel Motor for Machines with Serial Numbers Ending 6 Through 499 TN383 Figure -34: Left Front Wheel Motor for Machines with Serial Numbers Ending 6 Through 499 TN4668 Figure -33: Right Front Wheel Motor for Machines with Serial Numbers Ending 00 and Up 3. Install blocking disk at location () to block oil to right front wheel motor. TN4666 Figure -3: Left Front Wheel Motor for Machines with Serial Numbers Ending 00 and Up 4. Install blocking disk at location () to block oil to left front wheel motor Rev B

49 Verify engine rpm is within specification (30 rpm ± 0) to ensure accurate hydraulic test results. 7. Start engine and release park brake (park brake switch in the off position). 8. Depress traction pedal fully forward and set cruise control. 9. Verify flow is between 7 gpm (7 64 lpm). 0. Use the flow meter to warm the hydraulic oil. Turn the flow meter valve until a reading of 800 psi (4 bar) is reached. Warm oil to 0 0 F (49 6 C); open flow meter valve fully after operating temperature is reached.. After warming the hydraulic oil, verify cruise control is set to allow pump to produce 7 gpm (7 64 lpm) in the forward direction. Read and record no load flow.. Slowly close flow meter valve until a pressure of 700 psi (86 bar) is reached. Read and record loaded flow. 3. Disengage cruise control switch, engage park brake (park brake switch in the on position), and stop the engine. 4. Calculate traction pump leakage. (Step Step / Step x 00 = Leak Percentage) Figure -36: Traction Pump Test Blocking Disks Blocking Oil to Front Wheel Motors 3 TN3830 Is traction pump leakage 0% or less? YES The traction pump is good. Proceed to step. NO Proceed to next question. Is traction pump leakage % to 0%? YES The traction pump is marginal. Additional testing is required. Proceed to step. NO Proceed to next question. Is traction pump leakage % or more? YES Repair or replace traction pump. See Traction Pump on page -6, then proceed to step. Figure -37 TN37. Open flow meter valve (3) completely before starting engine. 6. Enter LCD maintenance mode and set MAX SPEED to 8 mph (3 km/h). (See LCD Maintenance Mode on page 4-44.) 446-Rev B -49

50 ! CAUTION For machines with serial numbers 6 through 499, do not exceed 3987 psi (7 bar) as damage may occur to hydraulic system components. For machines with serial numbers 00 and up, do not exceed 478 psi (330 bar) as damage may occur to hydraulic system components. 4. Open flow meter valve completely before starting engine. 6. Enter LCD maintenance mode and set MAX SPEED to 8 mph (3 km/h). (See LCD Maintenance Mode on page 4-44.) Verify engine rpm is within specification (30 rpm ± 0) to ensure accurate hydraulic test results. 7. Start engine and release park brake (park brake switch in the off position). 8. Depress traction pedal fully forward and set cruise control. 9. Verify flow is between 7 gpm (7 64 lpm). 0. Use the flow meter to warm the hydraulic oil. Turn the flow meter valve until a reading of 800 psi (4 bar) is reached. Warm oil to 0 0 F (49 6 C); open flow meter valve fully after operating temperature is reached.. Slowly close flow meter valve until zero flow is obtained. Record forward system relief valve pressure.. Open flow meter valve completely, disengage cruise control switch, engage park brake (park brake switch in the on position), and stop the engine. S For machines with serial numbers 6 through 499, the forward system relief pressure specification is 36 ± 0% psi (0 ± 0% bar). For machines with serial numbers 00 and up, the forward system relief pressure specification is 430 ± 0% psi (300 ± 0% bar). Does forward system relief pressure meet specification? YES Forward system relief valve is good. Proceed to Front Wheel Motors Tests on page -. NO Replace forward system relief valve. See Traction Pump on page -6, then proceed to Front Wheel Motors Tests on page -. Figure -38 Reverse system relief valve test is similar. 3. To test reverse system relief valve, swap hoses (4 and ) at flow meter. TN37 Verify engine rpm is within specification (30 rpm ± 0) to ensure accurate hydraulic test results. 4. Start engine and release park brake (park brake switch in the off position).. Depress traction pedal fully reverse and set cruise control. 6. Verify flow is between 7 gpm (9 7 lpm). 7. Slowly close flow meter valve until zero flow is obtained and record reverse system relief valve pressure. 8. Open flow meter valve completely, disengage cruise control switch, engage park brake (park brake switch in the on position), and stop the engine. 9. Swap hoses (4 and ) at flow meter. Is reverse system relief pressure 36 ± 0% psi (0 ± 0% bar)? YES Reverse system relief valve is good. Proceed to Front Wheel Motors Tests on page -. NO Replace reverse system relief valve. See Traction Pump on page -6, then proceed to Front Wheel Motors Tests on page Rev B

51 Front Wheel Motors Tests See Figures -39 through -47. IMPORTANT Performing this test will isolate the front wheel motors from the rest of the hydrostatic system. This test works together with the traction system test, traction pump tests, 4WD valve test, and rear wheel motors tests to isolate a problem within the hydrostatic power train. Right Front Wheel Motor Test See Figures -39 through -44.! WARNING The hydraulic system is under pressure, and the oil will be hot. Always relieve pressure in the hydraulic system before performing service. Failure to follow appropriate safety precautions may result in death or serious injury. TN3834 Figure -39: Right Front Wheel Motor for Machines with Serial Numbers Ending 6 Through 499 Required Tools and Materials Flow Meter - ORFS Test Hoses 000 psi (34 bar) -0 ORFS Test Hoses 000 psi (34 bar) - ORFS and -0 ORFS Blocking Disks Wheel Restraints. Park the mower safely. (See Park Mower Safely on page -6.). Before performing this test, perform traction pump test leaving rear of mower lifted and supported, and flow meter and front wheel restraints connected as outlined. (See Traction Pump Tests on page -47.) TN4668 Figure -40: Right Front Wheel Motor for Machines with Serial Numbers Ending 00 and Up 3. Remove blocking disk at location (). 446-Rev B -

52 Verify engine rpm is within specification (30 rpm ± 0) to ensure accurate hydraulic test results. 6. Start engine and release park brake (park brake switch in the off position). 7. Depress traction pedal fully forward and set cruise control. 8. Verify flow is between 7 gpm (7 64 lpm). 9. Use the flow meter to warm the hydraulic oil. Turn the flow meter valve until a reading of 800 psi (4 bar) is reached. Warm oil to 0 0 F (49 6 C); open flow meter valve fully after operating temperature is reached. 0. After warming the hydraulic oil, verify cruise control is set to allow pump to produce 7 gpm (7 64 lpm) in the forward direction.. Slowly close flow meter valve until a pressure of 700 psi (86 bar) is reached. Read and record loaded flow.. Disengage cruise control switch, engage park brake (park brake switch in the on position), and stop the engine. 3. Calculate right front wheel motor leakage. (Step of previous test Step / Step of previous test x 00 = Leak Percentage) Figure -4: Right Front Wheel Motor Test Blocking Disk Blocking Oil to Left Front Wheel Motor, Front Wheels Restrained TN3840 Is right front wheel motor leakage 0% or less? YES The right front wheel motor is good. Proceed to step 4. NO Proceed to next question. Is right front wheel motor leakage % to 0%? YES The right front wheel motor is marginal. Additional testing is required. Proceed to step 4. NO Proceed to next question. Is right front wheel motor leakage % or more? YES Repair or replace right front wheel motor. See Front Wheel Motor (Earlier Machines) on page -7 or Front Wheel Motor (Later Machines) on page -8, then proceed to step 4. Figure -4 TN37 4. Open flow meter valve () completely before starting engine.. Enter LCD maintenance mode and set MAX SPEED to 8 mph (3 km/h). (See LCD Maintenance Mode on page 4-44.) Rev B

53 Left Front Wheel Motor Test See Figures -4 through TN383 Figure -43: Left Front Wheel Motor for Machines with Serial Numbers Ending 6 Through 499 TN3834 Figure -4: Right Front Wheel Motor for Machines with Serial Numbers Ending 6 Through Figure -44: Left Front Wheel Motor for Machines with Serial Numbers Ending 00 and Up 4. Remove blocking disk from location (3). TN4666 TN4668 Figure -46: Right Front Wheel Motor for Machines with Serial Numbers Ending 00 and Up. Install blocking disk at location (4) to block oil to right front wheel motor. 446-Rev B -3

54 Figure -47: Left Front Wheel Motor Test Blocking Disk Blocking Oil to Right Front Wheel Motor, Front Wheels Restrained 6. Open flow meter valve completely before starting engine. 7. Enter LCD maintenance mode and set MAX SPEED to 8 mph (3 km/h). (See LCD Maintenance Mode on page 4-44.) TN384 Verify engine rpm is within specification (30 rpm ± 0) to ensure accurate hydraulic test results. 8. Start engine and release park brake (park brake switch in the off position). 9. Depress traction pedal fully forward and set cruise control. 0. Verify flow is between 7 gpm (7 64 lpm).. Use the flow meter to warm the hydraulic oil. Turn the flow meter valve until a reading of 800 psi (4 bar) or 0% of the forward relief valve rating is reached. Warm oil to 0 0 F (49 6 C); open flow meter valve fully after operating temperature is reached.. After warming the hydraulic oil, verify cruise control is set to allow pump to produce 7 gpm (7 64 lpm) in the forward direction. 3. Slowly close flow meter valve until a pressure of 700 psi (86 bar) or 7% of the relief valve rating is reached. Read and record loaded flow. 4. Disengage cruise control switch, engage park brake (park brake switch in the on position), and stop the engine.. Calculate left front wheel motor leakage. (Step of traction pump test Step 3 / Step of traction pump test x 00 = Leak Percentage) Is left front wheel motor leakage 0% or less? YES The left front wheel motor is good. Proceed to step 6. NO Proceed to next question. Is left front wheel motor leakage % to 0%? YES The left front wheel motor is marginal. Additional testing is required. Proceed to step 6. NO Proceed to next question. Is left front wheel motor leakage % or more? YES Repair or replace left front wheel motor. (See Front Wheel Motor (Earlier Machines) on page -7 or Front Wheel Motor (Later Machines) on page -8, then proceed to step 6.! WARNING Prevent personal injury. Use properly rated lifting devices. Always be sure load is balanced before lifting. Support the machine properly using jackstands. 6. Lower rear of machine to the ground. 7. Remove front wheel restraints. 8. Remove blocking disk at location (4). 9. Proceed to 4WD Test. (See 4WD Test on page -.) Rev B

55 4WD Test See Figures -48 through -. IMPORTANT Performing this test will isolate the 4WD valve from the rest of the hydrostatic system. This test works together with the traction system test, traction pump tests, front wheel motors tests, and rear wheel motors tests to isolate a problem within the hydrostatic power train.! WARNING The hydraulic system is under pressure, and the oil will be hot. Always relieve pressure in the hydraulic system before performing service. Failure to follow appropriate safety precautions may result in death or serious injury. Figure Install wheel restraint () to rear wheels. TN76 Required Tools and Materials Flow Meter - ORFS Test Hose 000 psi (34 bar) -0 ORFS Test Hose 000 psi (34 bar) - ORFS and -0 ORFS Blocking Disks Wheel Restraints. Park the mower safely. (See Park Mower Safely on page -6.). Before performing this test, perform front wheel motors tests leaving flow meter connected as outlined. (See Front Wheel Motors Tests on page -.) IMPORTANT! WARNING Prevent personal injury. Use properly rated lifting devices. Always be sure load is balanced before lifting. Support the machine properly using jackstands. It is important to lift and support the front of machine or the machine will move. Lift and support the machine so that the front wheels are off the ground. 3 Figure Install blocking disks at locations ( and 3). TN Rev B -

56 Figure -0. Install blocking disk at location (4). 4 TN Open flow meter valve completely before starting engine. 7. Enter LCD maintenance mode and set MAX SPEED to 8 mph (3 km/h). (See LCD Maintenance Mode on page 4-44.) Verify engine rpm is within specification (30 rpm ± 0) to ensure accurate hydraulic test results. 8. Start engine and release park brake (park brake switch in the off position). 9. Depress traction pedal fully forward and set cruise control. 0. Verify flow is between 7 gpm (7 64 lpm).. Use the flow meter to warm the hydraulic oil. Turn the flow meter valve until a reading of 800 psi (4 bar) is reached. Warm oil to 0 0 F (49 6 C); open flow meter valve fully after operating temperature is reached.. After warming the hydraulic oil, verify cruise control is set to allow pump to produce 7 gpm (7 64 lpm) in the forward direction. 3. Slowly close flow meter valve until a pressure of 700 psi (86 bar) is reached. Read and record loaded flow. 4. Disengage cruise control switch, engage park brake (park brake switch in the on position), and stop the engine.. Calculate 4WD valve leakage. (Step 3 of previous test Step 3 / Step 3 of previous test x 00 = Leak Percentage) Is 4WD valve leakage 0% or less? YES The 4WD valve is good. Proceed to Rear Wheel Motors Tests on page -7. NO Proceed to next question. Is 4WD valve leakage % to 0%? YES The 4WD valve is marginal. Inspect check valves and repair or replace as necessary. See 4WD on page -69, then proceed to step 6. NO Proceed to next question. Is 4WD valve leakage % or more? YES Inspect check valves and repair or replace as necessary. See 4WD on page -69, then proceed to step 6. TN909 Figure -: 4WD Test Blocking Disks Blocking Oil to Rear Wheel Inlets and Hot Oil Shuttle Outlet to Tank, and Rear Wheels Restrained Rev B

57 6. Retest 4WD valve. Is 4WD valve leakage 0% or less? YES The 4WD valve is good. Proceed to Rear Wheel Motors Tests on page -7. NO Proceed to next question. Is 4WD valve leakage % to 0%? YES The 4WD valve is marginal. Repair or replace 4WD valve as needed. See 4WD on page -69, then proceed to Rear Wheel Motors Tests on page -7. NO Proceed to next question. Is 4WD valve leakage % or more? YES Repair or replace 4WD valve. See 4WD on page -69, then proceed to Rear Wheel Motors Tests on page -7. Rear Wheel Motors Tests See Figures - through -4.. Before performing this test, perform 4WD valve test leaving front of mower lifted and supported, and flow meter and rear wheel restraints connected as outlined. (See 4WD Test on page -.) Left Rear Wheel Motor Test See Figures - and -3. IMPORTANT Performing this test will isolate the rear wheel motors from the rest of the hydrostatic system. This test works together with the traction system test, traction pump tests, front wheel motors tests, and 4WD valve test to isolate a problem within the hydrostatic power train. Figure - 3. Remove the blocking disk from location (). TN376! WARNING The hydraulic system is under pressure, and the oil will be hot. Always relieve pressure in the hydraulic system before performing service. Failure to follow appropriate safety precautions may result in death or serious injury. Required Tools and Materials Flow Meter - ORFS Test Hose 000 psi (34 bar) -0 ORFS Test Hose 000 psi (34 bar) - ORFS and -0 ORFS Blocking Disks Wheel Restraints. Park the mower safely. (See Park Mower Safely on page -6.) 446-Rev B -7

58 0. After warming the hydraulic oil, verify cruise control is set to allow pump to produce 7 gpm (7 64 lpm) in the forward direction.. Slowly close flow meter valve until a pressure of 700 psi (86 bar) is reached. Read and record loaded flow.. Disengage cruise control switch, engage park brake (park brake switch in the on position), and stop the engine. 3. Calculate left rear wheel motor leakage. (Step 3 of previous test Step / Step 3 of previous test x 00 = Leak Percentage) Is left rear wheel motor leakage 0% or less? YES The left rear wheel motor is good. Proceed to step 4. NO Proceed to next question. Is left rear wheel motor leakage % to 0%? YES The left rear wheel motor is marginal. Additional testing is required. Proceed to step 4. NO Proceed to next question. Is left rear wheel motor leakage % or more? YES Repair or replace left rear wheel motor. See Rear Wheel Motor on page -96, then proceed to step Remove blocking disk at location (). Figure -3: Left Rear Wheel Motor Test Blocking Disks Blocking Oil to Right Rear Wheel Inlet and Hot Oil Shuttle Outlet to Tank, and Rear Wheels Restrained 4. Open flow meter valve completely before starting engine.. Enter LCD maintenance mode and set MAX SPEED to 8 mph (3 km/h). (See LCD Maintenance Mode on page 4-44.) TN90 Verify engine rpm is within specification (30 rpm ± 0) to ensure accurate hydraulic test results. 6. Start engine and release park brake (park brake switch in the off position). 7. Depress traction pedal fully forward and set cruise control. 8. Verify flow is between 7 gpm (7 64 lpm). 9. Use the flow meter to warm the hydraulic oil. Turn the flow meter valve until a reading of 800 psi (4 bar) is reached. Warm oil to 0 0 F (49 6 C); open flow meter valve fully after operating temperature is reached Rev B

59 Right Rear Wheel Motor Test See Figure -4.. Install blocking disk at location (3). See Figure Use the flow meter to warm the hydraulic oil. Turn the flow meter valve until a reading of 800 psi (4 bar) is reached. Warm oil to 0 0 F (49 6 C); open flow meter valve fully after operating temperature is reached.. After warming the hydraulic oil, verify cruise control is set to allow pump to produce 7 gpm (7 64 lpm) in the forward direction. 3. Slowly close flow meter valve until a pressure of 700 psi (86 bar) is reached. Read and record loaded flow. 4. Disengage cruise control switch, engage park brake (park brake switch in the on position), and stop the engine.. Calculate right rear wheel motor leakage. (Step 3 of 4WD Test Step 3 / Step 3 of 4WD Test x 00 = Leak Percentage) Is right rear wheel motor leakage 0% or less? YES The right rear wheel motor is good. Proceed to step 6. NO Proceed to next question. Is right rear wheel motor leakage % to 0%? YES The right rear wheel motor is marginal. Repair or replace right rear wheel motor as necessary. See Rear Wheel Motor on page -96, then proceed to step 6. NO Proceed to next question. TN9 Figure -4: Right Rear Wheel Motor Test Blocking Disks Blocking Oil to Left Rear Wheel Inlet, and Hot Oil Shuttle Outlet to Tank, and Rear Wheels Restrained 6. Open flow meter valve completely before starting engine. 7. Enter LCD maintenance mode and set MAX SPEED to 8 mph (3 km/h). (See LCD Maintenance Mode on page 4-44.) Is right rear wheel motor leakage % or more? YES Repair or replace right rear wheel motor. See Rear Wheel Motor on page -96, then proceed to step Disconnect and remove test equipment. Install all hoses and fittings as noted prior to removal. 7. Install and connect all components as noted prior to test. 8. Check hydraulic oil level. Add oil as needed. (Refer to Parts and Maintenance Manual for correct oil specifications.) 9. Start engine. Check hydraulic system for leaks. Repair as necessary. Verify engine rpm is within specification (30 rpm ± 0) to ensure accurate hydraulic test results. 8. Start engine and release park brake (park brake switch in the off position). 9. Depress traction pedal fully forward and set cruise control. 0. Verify flow is between 7 gpm (7 64 lpm). 446-Rev B -9

60 Repair Drive Shaft Removal and Installation See Figure -.. Park the mower safely. (See Park Mower Safely on page -6.) Remove nut () and screw (). 3. Remove mounting screws (4) and washers (3). 4. Disconnect and remove drive shaft () from traction pump shaft (7). Figure - TN Rev B

61 Installation Notes Anti-Seize Compound Required Materials Install drive shaft by reversing the order of removal. Apply anti-seize to the drive shaft splines (6). Tip of traction pump shaft must be flush within 0. in. (3 mm) to the inside of the drive shaft yoke. Tighten mounting screws (4) to 3 40 lb-ft (47 4 N m). Clean grease fittings and lubricate with grease that meets or exceeds NLGI Grade LB specifications. Traction Pump Removal and Installation See Figures -6 and -7.. Park the mower safely. (See Park Mower Safely on page -6.). Drain hydraulic oil tank. (See Hydraulic Oil Tank Drain Procedure on page 6-.) 3. Remove gear pump. (See Gear Pump on page 6-.) Figure -6 TN Rev B -6

62 S Label all hydraulic hoses and tubes before disconnecting to ensure correct installation. Close all openings with caps or plugs to prevent contamination. 4. Disconnect hydraulic tubes (,, 6, and 9).. Disconnect drive shaft (). Installation Notes Install traction pump by reversing the order of removal. Ensure new O-rings are in place before installing hoses on fittings. Pressure filter the traction system. (See Portable In-Line Filter on page -7.) Refill hydraulic oil tank. (Refer to Parts and Maintenance Manual for correct oil specifications.) Start engine. Check for leaks and repair as necessary. Check hydraulic oil level. Add oil as needed. Perform neutral adjustments. (See Neutral Adjustments on page -36.) 0 Figure -7 Label wire connector before disconnecting to ensure correct installation. 6. Disconnect wire connector (0). TN37! WARNING The traction pump weighs approximately 3 lb (9 kg). Prevent personal injury. Use a properly rated lifting device. Always be sure the load is balanced before lifting. 7. Attach a suitable lifting device to the traction pump (8). 8. Remove nuts (3), lock washers (4), and screws (7). 9. Remove traction pump (8) Rev B

63 Disassembly, Inspection, and Assembly See Figures -8 through Figure -8 TN300 Record the location of fittings before removing to ensure correct installation.. Remove dust caps (3).. Remove, inspect, and replace test port fittings () as necessary. 3. Remove, inspect, and replace return tube fitting (), charge filter tube fitting (4), and fittings () for ports A and B as necessary. 446-Rev B -63

64 System Relief 9 O-Ring Charge Pressure Relief Front Cover Screw () 7 Tow 0 Charge Pressure Relief Screw 3 Front Cover Gasket 6 Shaft Seal 8 Back-Up Ring O-Ring 4 System Relief Figure -9 TN Rev B

65 TN99 7 Cover Plate Screw () 3 Servo Piston Cover Plug 8 Servo Piston Cover Screw () 33 EDC Mounting Screw 8 Auxiliary Pad Screw (3) 4 Servo Piston Cover Screw () 9 Seal Nut 34 EDC Mounting Screw 9 Temper Load Ring Servo Cover Gasket 30 EDC (Electronic Displacement Control) 3 Filtration Cover Screw (3) 0 O-Ring 6 Piston Ring Kit 3 O-Ring 36 Filtration Cover Plug Case Outlet Plug 7 Bearing Ring 3 O-Ring 37 Suction Filter Adapter Seal Plug Figure Rev B -6

66 4. Disassemble traction pump as shown in Figures -9 and Place parts, in assembly order, on a clean work area as they are removed. Inspection Notes NOTICE It is important that all pump parts are absolutely clean, as contamination can result in serious damage and/or improper operation. Never use shop towels or rags to dry parts after cleaning, as lint may clog passages. Dry parts using compressed air. Keeping parts in assembly order, clean and air dry each item for inspection. Inspect for worn or defective parts. Look for metal chips or slivers during cleaning (an indication of damage to pump or other hydraulic component). Inspect all parts for cracks, nicks, burrs, and excessive wear. Inspect for scoring, galling, and scratches on surfaces. Damage or excessive wear to traction pump components other than service components (6, 8 9, 4, 6, 9 0, 7, 9 3, and 37) requires traction pump replacement. Assembly Notes Required Materials Seal Kit (Jacobsen PN ) Shaft Seal Kit (Jacobsen PN psi System Relief Kit (Jacobsen PN ) 430 psi System Relief Kit (Jacobsen PN ) Charge Relief Kit (Jacobsen PN 440) O-Ring Charge Relief (Jacobsen PN 44) EDC Kit (Jacobsen PN 4440) EDC O-Ring (Jacobsen PN 4480) EDC Screw O-Ring (Jacobsen PN 448) Assemble the pump by reversing the order of disassembly. Install new O-rings and seals. Use clean grease to keep seals in position. Tighten test port fittings () to 7 lb-ft (3 N m). Tighten return tube fitting () to 80 lb-ft (08 N m). Tighten charge filter tube fitting (4) to 60 lb-ft (8 N m). Tighten fittings () for ports A and B to 00 lb-ft (3 N m). Tighten system relief valves (6 and 4) to 30 lb-ft (76 N m). Tighten tow valve (7) to lb-ft (0 N m). Tighten charge pressure relief screw (0) to 80 lb-ft (08 N m). Tighten front cover screws () to 43 lb-ft (8 N m). Tighten cover plate screws (7) to 7 lb-ft (77 N m). Tighten auxiliary pad screws (8) to 3 lb-ft (43 N m). Tighten case outlet plugs () to 8 lb-ft ( N m). Tighten plug () to lb-ft (0 N m). Tighten servo piston cover plugs (3) to 7 lb-ft (37 N m). Tighten servo piston cover screws (4 and 8) to lb-ft ( N m). Tighten seal nut (9) to 7 lb-ft (37 N m). Tighten EDC mounting screws (33 and 34) to 0 lb-ft (4 N m). Tighten filtration cover screws (3) to lb-ft (30 N m). Tighten filtration cover plug (36) to 7 lb-ft (37 N m) Rev B

67 Brake Release Removal and Installation See Figure -6.. Park the mower safely. (See Park Mower Safely on page -6.). Drain hydraulic oil tank. (See Hydraulic Oil Tank Drain Procedure on page 6-.) The brake release valve is located on the front right of the machine. 3. Thoroughly clean the valve, especially the area surrounding hydraulic hoses, tubes, and fittings. Installation Notes Install the brake release valve by reversing the order of removal. Lubricate all O-rings prior to assembly. Make sure new O-rings are in place before installing hoses on fittings. Apply dielectric grease (Jacobsen PN 364) to any wire connectors disconnected. Replace hydraulic oil filter and charge pressure filter. Refill hydraulic oil tank. (Refer to Parts and Maintenance Manual for correct oil specifications.) Start engine. Check hydraulic system for leaks. Repair as necessary. Check hydraulic oil level. Add oil as needed. Disassembly, Inspection, and Assembly See Figures -6 and Figure -6 Label wire connector before disconnecting to ensure correct installation. 4. Disconnect wire connector (). S TN376 Label all hydraulic hoses and tubes before disconnecting to ensure correct installation. Close all openings with caps or plugs to prevent contamination.. Disconnect hydraulic hoses (3, 4, 7, and 8). 6. Support the brake release valve (6). 7. Remove mounting screws (), and lock washers (). 8. Remove brake release valve (6). Figure -6 TN300 Record the location of fittings before removing to ensure correct installation.. Remove, inspect, and replace fittings () for ports ST and BR and fittings () for CHG and DRN ports as necessary. 446-Rev B -67

68 4 3 Assembly Notes NOTICE It is important that all component parts are absolutely clean, as contamination can result in serious damage and/or improper operation. Never use shop towels or rags to dry parts after cleaning, as lint may clog passages. Dry parts using compressed air Direction Control 8 Actuator 4 Direction Control Nut 9 Solenoid Handle Kit 0 Relief 6 Coil Check 7 Coil Nut Block Figure -63 TN300. Clean all parts using clean solvent, and dry using compressed air. 3. Inspect all parts for wear or damage. Replace parts as necessary. 6 Required Materials Direction Control Seal Kit (Jacobsen PN 4940) Check Seal Kit (Jacobsen PN 4940) Relief Seal Kit (Jacobsen PN 4940) Solenoid Seal Kit (Jacobsen PN 4336) Assemble the brake release valve by reversing the order of disassembly. Use a new direction control valve seal kit, check valve seal kit, relief valve seal kit, and solenoid valve seal kit during assembly. Lubricate all O-rings prior to assembly. Tighten direction control valve (3) to 30 3 lb-ft ( N m). Tighten direction control valve nut (4) to lb-in. ( N m). Tighten coil nut (7) to 3 3 lb-in. (4 6 N m). Tighten solenoid valve (9) to 6 30 lb-ft ( N m). Tighten relief valve (0) and check valve () to 0 lb-ft ( N m). Tighten fittings () for ports ST and BR to 7 lb-ft (3 N m). Tighten fittings () for CHG and DRN ports to 7 lb-ft (3 N m). Apply dielectric grease (Jacobsen PN 364) to any wire connectors disconnected Rev B

69 4WD Removal and Installation See Figures -64 and -6.. Park the mower safely. (See Park Mower Safely on page -6.). Drain hydraulic oil tank. (See Hydraulic Oil Tank Drain Procedure on page 6-.) 3 4 Figure -64 The 4WD valve is located on the rear of the machine. 3. Thoroughly clean the valve, especially the area surrounding hydraulic hoses, tubes, and fittings. S TN376 Label all hydraulic hoses and tubes before disconnecting to ensure correct installation. Close all openings with caps or plugs to prevent contamination. 4. Disconnect hydraulic tubes ( and 6).. Disconnect hydraulic hoses (, 4,, and 0). 6. Support the 4WD valve (3). 7. Remove four mounting screws (7), lock washers (8), and flat washers (9). 6 Figure -6 TN Disconnect hydraulic tubes ( and ). 9. Remove 4WD valve (3). Installation Notes Install the 4WD valve by reversing the order of removal. Lubricate all O-rings prior to assembly. Make sure new O-rings are in place before installing hoses on fittings. Apply dielectric grease (Jacobsen PN 364) to any wire connectors disconnected. Replace hydraulic oil filter and charge pressure filter. Refill hydraulic tank. (Refer to Parts and Maintenance Manual for correct oil specifications.) Start engine. Check hydraulic system for leaks. Repair as necessary. Check hydraulic oil level. Add oil as needed. 446-Rev B -69

70 Disassembly, Inspection, and Assembly See Figures -66 and Clean all parts using clean solvent, and dry using compressed air.. Inspect all parts for wear or damage. Replace parts as necessary. Assembly Notes 4 NOTICE It is important that all component parts are absolutely clean, as contamination can result in serious damage and/or improper operation. Never use shop towels or rags to dry parts after cleaning, as lint may clog passages. Dry parts using compressed air. 3 Figure -66 TN4736 Record the location of fittings before removing to ensure correct installation.. Remove, inspect, and replace fittings () for ports LRF, LRR, RRF, and RRR as necessary.. Remove, inspect, and replace fittings () for ports LF and RF as necessary. 3. Remove, inspect, and replace DRN port fitting (3) and REV port fitting (4) as necessary Required Materials Check Seal Kit (Jacobsen PN 490) Relief Seal Kit (Jacobsen PN 490) Hot Oil Shuttle Seal Kit (Jacobsen PN 4940) Assemble the 4WD valve by reversing the order of disassembly. Use a new check valve seal kit, relief valve seal kit, and hot oil shuttle seal kit during assembly. Lubricate all O-rings prior to assembly. Tighten check valves (6), hot oil shuttle (8), and relief valve (9) to 30 3 lb-ft ( N m). Tighten fittings () for ports LRF, LRR, RRF, and RRR to 0 lb-ft (49 N m). Tighten fittings () for ports LF and RF to 0 lb-ft (49 N m). Tighten DRN port fitting (3) to lb-ft (34 N m). Tighten REV port fitting (4) to 60 lb-ft (7 N m). Apply dielectric grease (Jacobsen PN 364) to any wire connectors disconnected. 0 9 Block 8 Hot Oil Shuttle 6 Check 9 Relief 7 Orifice Plug 0 Tapered Plug (6) Figure -67 TN Rev B

71 Front Wheel Motor (Earlier Machines) This procedure is for machines with the following serial numbers: Serial No ~ 499 Serial No ~ 499 Serial No ~ 499 Serial No ~ 499 Serial No ~ 499 Serial No ~ 499 Removal and Installation See Figure Park the mower safely. (See Park Mower Safely on page -6.). Remove front wheel. (See Front Wheel (Earlier Machines) on page 9-8.) 3. Remove front wheel hub. (See Front Wheel Hub (Earlier Machines) on page 9-9.) 6. Support front wheel motor (8) and remove four mounting screws (7) and lock washers (6). 7. Remove front wheel motor (8). Installation Notes Install front wheel motor by reversing the order of removal. Tighten front wheel motor mounting screws (7) to 8 9 lb-ft ( 9 N m). Tighten brake release port fitting () and case drain fitting (9) to lb-in. (0 N m). Tighten inlet and outlet port fittings () to 0 lb-ft (49 N m). Pressure filter the traction system upon start-up if metal debris is found in system oil or motor. (See Portable In-Line Filter on page -7.) Check hydraulic oil level. Add oil as needed. (Refer to Parts and Maintenance Manual for correct oil specifications.) Start engine. Check hydraulic system for leaks. Repair as necessary. ~ TN989 Figure -68 S Label all hydraulic hoses and tubes before disconnecting to ensure correct installation. Close all openings with caps or plugs to prevent contamination. 4. Disconnect hoses (3, 4,, and 0). Record the location of fittings before removing to ensure correct installation.. Remove brake release port fitting (), inlet and outlet port fittings (), and case drain fitting (9). 446-Rev B -7

72 Disassembly and Inspection See Figures -69 through Figure -7 TN3 Figure -69. Scribe a line () along the side of hydraulic motor sections () to mark the position of motor segments before disassembly. 3 4 TN309 Spacer (9) may remain with disk valve (6) when the valve housing is removed. 3. Remove end cover assembly (8) and spacer (9) from disk valve (6) and valve plate (). 4. Remove disk valve (6) from valve drive (7) and valve plate (). 0 ~ ~ Figure -70 TN30 Use caution when removing screws, as motor segments will be free to move.. Remove seven screws (3) from the end cover (4). Figure -7. Remove O-ring (0) from valve plate (). TN3 Record the orientation of the valve drive before removing to ensure correct installation. 6. Remove valve plate () from gear wheel set () Rev B

73 ~ Figure Remove O-ring (3) from gear wheel set (). 8. Remove valve drive (4) from gear wheel set (). S 6 TN33 The gear wheel set components are loose and can fall apart when removed. When removing use caution and remove the gear wheel set as a unit. Do not disassemble the gear wheel set. If replacement is necessary, replace the entire assembly. 9. Remove gear wheel set () from mounting flange/bearing housing assembly (6). 9 Figure Remove O-ring (7) from mounting flange assembly (9).. Remove drive shaft (8) from mounting flange assembly (9). 0 TN Figure -7 TN3. Remove eight socket-head screws (0) and remove bearing housing assembly () from mounting flange assembly (). 446-Rev B -73

74 3 4. Inspect the friction surfaces (7) (front and rear). Replace the stator rings (6) if the surfaces are worn or damaged, or if any other damage is noted. 8 9 ~ Figure -76 Record the order of brake disks and stator rings to ensure correct assembly. 3. Remove five brake disks (3) and six stator rings (4) from mounting flange assembly (). 4 TN36 6 Figure -78. Inspect the disks for any scratches on the mating surfaces (9) (front and rear). Replace the disks (8) if any damage is noted TN30 34 ~ 7 TN39 Figure -77 Always replace the stator rings and brake discs as a set. Figure -79 TN339 Record the orientation of the brake piston (30) and spring discs (33) before removing to ensure correct installation Rev B

75 6. Apply compressed air to vent (34), and remove brake piston (30), O-rings (3 and 3), and two spring disks (33) from mounting flange (3). 9. Remove shaft assembly (43) from bearing housing (4) using a press. Record the orientation of the dust seal (40) and shaft seal (4) before removing to ensure correct installation. 0. Remove dust seal (40) and shaft seal (4) from the bearing housing (4) Figure Remove O-ring (36) from bearing housing (37). 8. Remove retaining ring (39) from bearing housing (37) by inserting a pick or small screwdriver in the opening (38) in the bearing housing and carefully prying the end of the retaining ring out of the groove TN37 ~ Figure -8 TN34. Fill the hole in the center of balance plate (46) with oil, and install spacer (4).. Tap spacer (4) using a soft-faced hammer (44) to loosen the balance plate (46) Figure -8 TN340 Support the base of the bearing housing (4) and apply pressure to the end of the shaft assembly. Figure -83 TN Rev B -7

76 3. Remove spacer (47), balance plate (48), and spring washers (49) from the end cover (0). Assembly See Figures -8 through -99. NOTICE It is important that all motor parts are absolutely clean, as contamination can result in serious damage and/or improper operation. Never use shop towels or rags to dry parts after cleaning, as lint may clog passages. Dry parts using compressed air only. 3 Required Materials Seal Kit (Jacobsen PN 4844) Figure -84 Record the location of the backing rings before removing to ensure correct installation. 4. Remove O-ring (4) and backing ring (3) from balance plate ().. Remove O-ring () and two backing rings () from balance plate (). NOTICE TN343 It is important that all motor parts are absolutely clean, as contamination can result in serious damage and/or improper operation. Never use shop towels or rags to dry parts after cleaning, as lint may clog passages. Dry parts using compressed air only. 6. Clean all parts using clean solvent, and dry using compressed air. 7. Inspect all parts for wear or damage. Replace parts as needed. 8. Apply a thin film of clean hydraulic oil to all parts to prevent corrosion. Keep parts covered or stored in a clean environment until assembly. 4 Always install new seals and O-rings for assembly. Used parts may leak. Figure -8. Apply a thin film of petroleum jelly to the inner and outer surfaces of the dust seal () and shaft seal (3). TN340 Install the seals using a seal and driver set and press.. Install shaft seal (3) in bearing housing (). 3. Install dust seal () in bearing housing (). 4. Support bearing housing (), and place the shaft assembly (4) into the housing/seals. Install shaft assembly into the housing using a suitable press Rev B

77 9. Install brake piston (8) in mounting flange () in the same orientation as recorded during removal. 3 4 ~ 6 7 Figure -86. Install retaining ring (7) into the groove in bearing housing (6). 6. Apply a thin film of petroleum jelly to O-ring (), and install O-ring on bearing housing (6) TN Figure Install brake disks (6) and stator rings (3) in bearing housing () and output shaft (4). Install a stator ring (3) first, aligning the tabs with the detents in the bearing housing (), followed by a brake disk (6), installed over the output shaft splines. Continue installation by alternating a stator ring and brake disk. 7 TN Figure -87 TN Install spring discs () in mounting flange () in the same orientation as recorded during removal. 8. Apply a thin film of petroleum jelly to O-rings (9 and 0), and install O-rings on the brake piston (8). 7 Figure TN3 446-Rev B -77

78 . Install mounting flange assembly (9) on bearing housing assembly (8) using eight socket-head screws (7). Tighten screws using an alternating pattern to 7 lb-ft (37 N m). IMPORTANT The motor must be timed correctly ~ Figure -90 TN34. Install drive shaft () in mounting flange assembly (). 3. Apply a thin film of petroleum jelly to O-ring (0), and install an O-ring in mounting flange assembly (). Figure -9 TN33 4. Install the gear wheel set (4) on mounting flange/bearing housing assembly ().. Apply a thin film of petroleum jelly to O-ring (3). Install O-ring on the gear wheel set (4). ~ 6 7 Figure -9: Correct Motor Timing TN Mark the gear wheel set rotor (7) at the point where the tip of a spline tooth is opposite to the bottom of a tooth in the external rotor teeth Rev B

79 l HYDROSTATIC POWER TRAIN 7. Mark the bottom of a spline on both ends of the valve drive (6). 8. Line up mark on gear wheel set rotor (7) with marks on valve drive (6) ~ 3 37 Figure TN343 TN33 Figure Install valve drive (6) in gear wheel set (8) Install the backing rings in the same locations as recorded during removal.. Install O-ring (34) and two backing rings (37) on balance plate (33). 3. Install O-ring (3) and backing ring (36) on balance plate (33). ~ ~ 3 Figure Install valve plate (30) on gear wheel set (3) with the oval ports (3) facing away from the gear wheel set.. Install O-ring (9) on valve plate (30). TN3 Figure -96 TN34 4. Install spring washers (40) and balance plate (39) in end cover (4).. Apply a thin film of petroleum jelly to spacer (38), and install spacer in the end cover assembly (4). 446-Rev B -79

80 ~ 43 Figure -97: Correct Motor Timing 6. Align mark on valve drive (43) with a hole in the outer rim of disk valve (4) TN366 Figure Install seven screws (46) in the end cover (47). Tighten screws using an alternating pattern to lb-ft (70 N m). TN30 4 Figure Install disk valve (4) on valve drive (43) and valve plate (44). 8. Install the end cover assembly (4) over the disk valve (4) and valve plate (44). TN Rev B

81 Front Wheel Motor (Later Machines) This procedure is for machines with the following serial numbers: Serial No and Up Serial No and Up Serial No and Up Serial No and Up Serial No and Up Serial No and Up Removal and Installation See Figure Park the mower safely. (See Park Mower Safely on page -6.). Remove front wheel. (See Front Wheel (Later Machines) on page 9-0.) Support front wheel motor () and remove eight mounting nuts (). 6. Remove front wheel motor () and eight wheel motor mounts (). 7. Inspect eight studs () for damage and replace as necessary. Apply Loctite 4 (Blue) to the threads on the axle side of studs () if stud is removed. Installation Notes Install front wheel motor by reversing the order of removal. Tighten front wheel motor mounting nuts (9) to 90 lb-ft ( N m). Tighten brake port fitting (3) to 7 lb-ft (3 N m). Tighten case drain fitting (0) to 30 lb-ft (4 N m). Tighten inlet and outlet port fittings ( and 8) to 90 lb-ft ( N m). Pressure filter the traction system upon start-up if metal debris is found in system oil or motor. (See Portable In-Line Filter on page -7.) Check hydraulic oil level. Add oil as needed. (Refer to Parts and Maintenance Manual for correct oil specifications.) 8. Start engine. Check hydraulic system for leaks. Repair as necessary. Figure -00 TN4666 S Label all hydraulic hoses and tubes before disconnecting to ensure correct installation. Close all openings with caps or plugs to prevent contamination. 3. Disconnect tubes (4, 6, 7, and 9). Record the location of fittings before removing to ensure correct installation. 4. Remove brake port fitting (3), case drain fitting (0), inlet port fitting (), and outlet port fitting (8). 446-Rev B -8

82 Spring Washer Compression Tools See Figure -0. Required Tools or Equipment Spring Washer Compression Tool Bolt and Nut Spring Washer Compression Tool Outer Roller Bearing Inner Race Installation Tool See Figure -0. Required Tools or Equipment Outer Roller Bearing Inner Race Installation Tool TN4667, TN in. (0 mm) 3.6 in. ( mm) Ø.9 in. (49. mm) Ø Figure -0: Outer Bearing Inner Race Installation Tool Outer Roller Bearing Outer Race Installation Tool See Figure TN467 M x 0 mm Bolt.8 in. (30 mm) Class 0.9 Threaded Full Length Hh Nut in. (00 mm) Ø 3 0. in. (3 mm) Ø Hole in. (0 mm) Ø in. (0 mm) Figure -0: Spring Washer Compression Tools Required Tools or Equipment Outer Roller Bearing Outer Race Installation Tool TN in. (0 mm) 3.30 in. (84 mm) Ø Figure -03: Outer Roller Bearing Outer Race Installation Tool Rev B

83 Inner Roller Bearing Inner Race Installation Tool See Figure -04. Required Tools or Equipment Inner Roller Bearing Inner Race Installation Tool Inner Roller Bearing Outer Race Installation Tool See Figure -0. Required Tools or Equipment Inner Roller Bearing Outer Race Installation Tool in. (0 mm) 3.0 in. (89 mm) Ø Figure -0: Inner Roller Bearing Outer Race Installation Tool TN in. (37 mm) 4.8 in. (8 mm) Ø 4.3 in. ( mm).60 in. (66 mm) Ø 3.73 in. (44 mm) Figure -04: Inner Roller Bearing Inner Race Installation Tool TN Rev B -83

84 Shaft Seal Installation Tool See Figure -06. Required Tools or Equipment Shaft Seal Installation Tool Knurl in. (0 mm).38 in. (3 mm) Ø 7.8 in. (30 mm) in. (0 mm) 8.89 in. (48 mm) Ø in. (00 mm) 9.43 in. (6.7 mm) Ø M6 Figure -06: Shaft Seal Installation Tool TN Rev B

85 Front Wheel Motor (Later Machines) Disassembly See Figures -07 through Motor Shaft 3 Stud () 4 Backup Ring 3 Snap Ring Environmental Seal 4 Valving Brake Shaft 36 Spring Washer 3 Outer Roller Bearing Seal Ring 6 External Brake Discs () 37 Screws (0) 4 Bearing Support 6 Seal Ring 7 Internal Brake Discs (0) 38 Brake Housing Radial Lip Seal (with Spring) 7 Seal Ring 8 Shim(s) 39 Plug 6 Inner Roller Bearing 8 Valving Cover 9 Sealing Washer 40 Seal 7 Shim Spacer 9 Sealing Washer 30 Screw 4 Screw () 8 Snap Ring 0 Screw 3 O-Ring 4 Backup Ring 9 Seal O-Ring 3 Brake Piston 43 Backup Ring 0 Cam Ring Bushing 33 Brake Cover 44 Backup Ring Seal 3 O-Ring 34 Plug 4 Spring Rotational Group Figure -07 TN Rev B -8

86 Brake Disassembly First Method with a Mandrel and Bolt IMPORTANT Figure -08 TN468 Inspect all parts for cracks, nicks, burrs, and excessive wear during disassembly. Damage or excessive wear to wheel motor components other than seal kit components (,, 7 9,, 7, 9,, 4, 9, 3, 33 34, and 4 44) requires wheel motor replacement.. Install wheel lug nuts (47) on studs (3) to prevent damage to the stud threads and place the wheel motor on the bearing support so that the brake end of the wheel motor is facing up.. Scribe alignment mark (46) across the side of the brake housing (38), valving cover (8), cam ring (0), and bearing support (4) of the front wheel motor. This mark will be used for proper orientation of components for assembly. 3. Using a pry tool, remove and discard brake cover (33). 4. Compress spring washer (36) by one of the following two methods: 47 Figure -09 a. Install the spring washer compression tool onto spring washer (36). b. Lubricate the spring compression tool bolt threads and nut faces and tighten the spring compression tool bolt into brake piston (3) down to the thread root. c. Compress spring washer (36) by tightening the spring compression tool nut and locking the spring compression tool bolt until motor shaft () turns freely. Second Method with a Mandrel and Press TN4680 Figure -0 TN468 a. Install the spring compression tool onto spring washer (36). b. Position the bearing support under a press to avoid any force on the studs. c. Compress spring washer (36) until motor shaft () turns freely Rev B

87 Mark the mounting direction of snap ring (34) prior to removal.. Remove snap ring (3), spring washer (36), and brake piston (3). 6. Remove and discard O-ring (3). 7. Remove ten screws (37) and remove brake housing (38). When removing shims (8), mark the assembly order and note the quantity and total thickness of shims. 8. Remove shims (8) and brake discs (6 and 7). 9. Remove and discard O-ring (). 0. Remove brake shaft ().. Remove and discard back up ring (4) and O-ring (3).. Remove and discard bushing (). Motor Disassembly Figure - Be careful not to lose rotational group sub-assembly components (48) during rotational group removal.. Remove cam ring (0) and rotational group (). 6. Remove and discard O-ring (). 7. Remove and discard O-ring (9). 8. Remove valving (4). 9. Remove spring (4) from valving (4). 0. Remove and discard seal rings ( 7) and back-up rings (4 44).. Position the bearing support under a press on the motor shaft () or on a support to avoid any force on the studs. 48 TN436 Figure - 3. Remove twelve screws (4). TN469 During valving cover (8) removal, valving (4) may remain in valving cover. Hold valving during valving cover removal. 4. Remove valving cover (8). Figure -3. Using inner roller bearing inner race installation tool (0) and press (49), apply a force on inner roller bearing (6) just enough to provide clearance for snap ring (8) removal TN Rev B -87

88 3. Remove snap ring (8). 4. Release press force and remove inner roller bearing inner race installation tool. When removing shim spacer (7), measure and note the thickness of the shim spacer.. Remove shim spacer (7). 3 4 Figure -4 TN Secure bearing support (4) to a suitable press fixture () and position press fixture on supports (3) under a press () with enough clearance to remove motor shaft (). 7. Remove motor shaft (). 8. Remove roller bearing (6) and radial lip seal (). 3 4 Figure - TN Install a bearing puller (4) under environmental seal (). 30. Remove environmental seal () and roller bearing (3). Discard environmental seal Rev B

89 Front Wheel Motor (Later Machines) Assembly See Figures -6 through Motor Shaft 3 Stud () 4 Backup Ring 3 Snap Ring Environmental Seal 4 Valving Brake Shaft 36 Spring Washer 3 Outer Roller Bearing Seal Ring 6 External Brake Discs () 37 Screws (0) 4 Bearing Support 6 Seal Ring 7 Internal Brake Discs (0) 38 Brake Housing Radial Lip Seal (with Spring) 7 Seal Ring 8 Shim(s) 39 Plug 6 Inner Roller Bearing 8 Valving Cover 9 Sealing Washer 40 Seal 7 Shim Spacer 9 Sealing Washer 30 Screw 4 Screw () 8 Snap Ring 0 Screw 3 O-Ring 4 Backup Ring 9 Seal O-Ring 3 Brake Piston 43 Backup Ring 0 Cam Ring Bushing 33 Brake Cover 44 Backup Ring Seal 3 O-Ring 34 Plug 4 Spring Rotational Group Figure -6 TN Rev B -89

90 Motor Assembly NOTICE It is important that all component parts are absolutely clean, as contamination can result in serious damage and/or improper operation. Never use shop towels or rags to dry parts after cleaning, as lint may clog passages. Dry parts using compressed air. Required Materials Front Motor Seal Kit (Jacobsen PN 490) Multi-Disc Seal Kit (Jacobsen PN 49) Loctite 638 Retaining Compound Loctite 747 Activator Mobilux EP Grease. Install new environmental seal () with lips facing out.. Lubricate lips of environmental seal () with Mobilux EP grease. 3. Position motor shaft () under a press to avoid any force on the studs. 4. Using a press, install bearing support (4) on motor shaft ().. Using the inner roller bearing inner race installation tool and a press, install inner roller bearing (6) and inner race in inner roller bearing outer race. Do not exceed,364 lb force. 6. Install shim spacer (7) of correct thickness as noted during removal. 7. Install snap ring (8). C Cm IMPORTANT Inspect all parts for cracks, nicks, burrs, and excessive wear during assembly. Damage or excessive wear to wheel motor components other than seal kit components (,, 7 9,, 7, 9,, 4, 9, 3, 33 34, and 4 44) requires wheel motor replacement.. Position bearing support (4) with motor shaft mating face seated on a flat surface.. Remove the spring from new radial lip seal (). 3. Using the shaft seal installation tool and a soft-faced hammer, install new radial lip seal () in bearing support (4). 4. Reinstall the radial lip seal spring.. Using the inner roller bearing outer race installation tool and a soft-faced hammer, install the outer race of roller bearing (6) in bearing support (4) up to the stop. 6. Position bearing support (4) with cam ring mating face seated on a flat surface. 7. Using the outer roller bearing outer race installation tool and a soft-faced hammer, install the outer race of roller bearing (3) in bearing support (4) up to the stop. 8. Lubricate the outer race of roller bearing (3) and the lips of radial lip seal () with Mobilux EP grease. 9. Lubricate outer roller bearing (3) and inner race with Mobilux EP grease. 0. Using the outer roller bearing inner race installation tool and a soft-faced hammer, install outer roller bearing (3) and inner race in outer roller bearing outer race. 6 F R Figure -7 TN Check bearing support rotation torque as follows: a. Install and tighten one screw (4) in bearing support (4) mounting hole. b. Position bearing support assembly under a press to avoid any force on the studs. c. Install a dial torque wrench (46) on screw (4). d. Measure and record distance (R) from center of motor shaft to center of screw (4). e. Measure and record distance (L) from center of screw (4) to point on torque wrench handle where hand force is applied. 4 L Rev B

91 f. Using the press and inner roller bearing inner race installation tool, apply,364 lb (,000 N) force (F) to bearing (6) for five seconds, then reduce force to 68 lb (70 N). g. Measure and record the torque (Cm) necessary to rotate bearing support (4). h. Determine the bearing support rotation torque: C = Cm x (R+L)/L i. If bearing support rotation torque is not within 8.8 ± 30% lb-ft ( ± 30% N m), remove snap ring (8) and replace shim spacer (7) with a thinner shim spacer (to decrease torque) or thicker shim spacer (to increase torque). j. Repeat steps a through i as necessary to meet specification. k. Remove screw (4). 9. Lubricate new O-ring (9) with Mobilux EP grease and install O-ring in bearing support (4). 0. Lubricate new O-ring () with Mobilux EP grease and install O-ring in valving cover (8). There are three different size seal rings and backup-rings. Install the smallest seal ring to the deepest groove first.. Install new seal rings ( 7) in valving cover (8), smallest first.. Install new backup rings (4 44) in valving cover (8), smallest first. 47 Figure Using grease, insert spring (4) into hole (47) of valving cover (8). IMPORTANT TN437 Make sure timing notch in valving (4) aligns with locating pin in valving cover (8) when installing valving in valving cover. 4. Install valving (4) in valving cover (8).. Install rotational group (). 0 4 Figure Using alignment mark (48) previously scribed on the wheel motor, install cam ring (0) on bearing support (4). 8 Make sure alignment of timing notch in valving (4) and locating pin in valving cover (8) is maintained when installing valving cover. 7. Install valving cover (8) in line with the marks made during disassembly. 8. Center the cam by installing two screws (4) 80 apart. 9. Install screws (4) and tighten to 6 ± 0% lb-ft (83 ± 0% N m) using an alternating pattern. Brake Assembly IMPORTANT TN469 When removing retaining compound residue from valving cover (8), do not scratch the surface. The original surface finish must be maintained. 30. Ensure any dried retaining compound on the bushing mating surfaces of valving cover (8) is removed. Scrape off all retaining compound residue with a blade or fine (00 grit) sandpaper. 3. Clean/degrease a new bushing () and the bushing mating surfaces of valving cover (8) with isopropyl alcohol. 3. Apply Loctite 638 retaining compound to the external diameter of bushing () and position bushing on valving cover (8) with the chamfer of the bushing facing toward the valving cover. 33. Using the large diameter end of brake shaft () and a soft-faced hammer, install bushing () into valving cover flush to in. (0. mm) below surface Rev B -9

92 34. Remove excess retaining compound from each side of bushing. 3. Install new O-ring (3) and new backup ring (4). 36. Install brake shaft (). 37. Apply Mobilux EP to the brake housing (38) brake shaft grooves and brake O-ring contact surface, and to the top of the brake piston (3), spring washer (36), and snap ring (3) IMPORTANT When removing retaining compound residue from valving cover (8) or brake housing (38), do not file or emery the surface. The original surface finish must be maintained. 38. Ensure any dried retaining compound on the brake housing mating surfaces of valving cover (8) and brake housing (38) is removed. Scrape off all retaining compound residue with a blade. Figure -0 TN467 IMPORTANT After degreasing with isopropyl alcohol, do not touch the mating surfaces of the valving cover and brake housing with hands or fingers. 39. Clean/degrease the brake housing mating surfaces of valving cover (8) and brake housing (38) with isopropyl alcohol. IMPORTANT After applying activator, do not touch the brake housing mating surface of the valving cover. Do not apply any activator on the brake shaft. 40. Apply a film of Loctite 747 activator on the brake housing mating surface of the valving cover (8), and wait minutes before continuing procedure. Do not apply any activator on brake shaft (). 4. Install new O-ring () in valving cover. IMPORTANT When placing bead of Loctite 638 retaining compound on valving cover, make sure no retaining compound is placed on the O-ring groove (). Step 43 must be completed within 0 minutes of applying Loctite 638 retaining compound in step Place a in. ( 0 mm) wide continuous bead (no gaps) of Loctite 638 retaining compound (49) on valving cover (8) following the median line (0) of the mounting screw hole centers. IMPORTANT The glued connection remains fragile up to six hours after being glued. During this time, avoid any shock to the glued parts; do not use or test the brake or the wheel motor. 43. Place brake housing onto valving cover and install ten screws (37). Tighten screws to 07 ± 0% lb-ft (4 ± 0% N m) in an alternating pattern Rev B

93 Lubricate spring washer (36) with Mobilux EP grease and install spring washer on brake piston (3).. Compress spring washer (36) by one of the two methods described in Front Wheel Motor (Later Machines) Disassembly on page -8.. Install snap ring (3) in line with the mark made prior to removal. 3. Lubricate seal in brake cover (33) with Mobilux EP grease. 6 External Brake Disc 7 Internal Brake Disc Figure - TN Lubricate twenty-one external brake discs (6) and twenty internal brake discs (7) with hydraulic fluid. 4. Install one external brake disc (6), then one internal brake disc (7). Continue alternately installing external and internal brake discs. The last brake disc installed must be an external disc (6). 46. Install the proper shims (8) of correct thickness and assembly order as noted during removal. 47. Lubricate the piston seal contact surface in the brake housing with Mobilux EP grease. 48. Install new O-ring (3) on brake piston (3). Make sure O-ring is not twisted after installation. When installing the brake cover, make sure that the outer edge of the brake cover is engaged in the groove. 4. Place new brake cover (33) on brake housing chamfer and click into place using a soft-faced hammer.. Install new plug (34) in brake cover (33). 6. Install front wheel motor. (See Front Wheel Motor (Later Machines) on page -8.) 7. Pressure filter the traction system upon start-up if metal debris is found in system oil or motor. (See Portable In-Line Filter on page -7.) 3 38 Figure - TN4694 When installing brake piston (3), begin installation by tipping one end of brake piston into brake housing (38). 49. Install brake piston in brake housing. 446-Rev B -93

94 Front Axle Assembly Removal and Installation See Figures -3 through -7.. Park the mower safely. (See Park Mower Safely on page -6.) Note location and routing of hydraulic hoses, tubes, electrical wires, and cable ties prior to removal and label all hydraulic hoses, tubes, and electrical wires before disconnecting to ensure correct installation.. Remove platform. (See Platform on page 9-.) 3. Remove traction pump. (See Traction Pump on page -6.) 4. Remove rear reel valve. (See Rear Reel on page 6-60.). Remove front reel valve. (See Front Reel on page 6-63.) 6. Remove lift valve. (See Lift on page 6-7.) 7. Remove reel level proximity switch. (See Reel Level Proximity Switch on page 4-8.) 8. Remove front and center lift cylinders. (See Left and Right Front Lift Cylinders on page 6-7 and Center Lift Cylinder on page 6-68.) 9. Remove front lift arms. (See Lift Arms on page 8-4.)! WARNING Support the machine using properly rated jackstands. Never work under a machine supported only by a jack. Do not use wood or concrete blocks to support the machine. Failure to properly support the machine may result in death or serious injury. 0. Block both sides of rear wheels using suitable wheel blocks.. Raise the machine so front wheels are off the ground. Place jackstands under the frame to support the machine.. Remove front wheel motors. (See Front Wheel Motor (Earlier Machines) on page -7 or Front Wheel Motor (Later Machines) on page -8.) 4 3 Figure Remove clamp screws (,, and 4). 4. Remove cable tie (3). 6 Figure -4. Remove clamp screws ( and 6). TN3773 TN Rev B

95 Figure - 6. Disconnect hoses (8 and 0). TN Disconnect tube (7). 8. Remove clamp nut (9). Slide clamp off stud Figure -7 TN Support the front axle assembly (6) with a suitable lifting device.. Ensure all hydraulic hoses, tubes and electrical wires are clear of front axle.. Remove eight nuts (4), lock washers (), flat washers (3), screws () and remove front axle assembly (6). 3. Remove, inspect, and replace six bushings (7) as necessary. Figure Remove clamp screws (). TN3783 Installation Notes Install the front axle by reversing the order of removal. Route all hydraulic hoses, tubes, and electrical wires as noted prior to removal, avoiding pinch points. Apply dielectric grease (Jacobsen PN 364) to any wire connectors disconnected. Use new cable ties to secure hydraulic hoses, tubes, and electrical wires. Tighten screws () to 8 lb-ft ( 30 N m). 446-Rev B -9