NAG 1/W5A580 Automatic Transmission Diagnosis and Repair

Transcription

1 NAG 1/W5A580 Automatic Transmission Diagnosis and Repair Student Workbook DAIMLERCHRYSLER ACADEMY School of Technical Training School of Technical Training

2 TABLE OF CONTENTS INTRODUCTION... 1 STUDENT LEARNING OBJECTIVES... 2 ACRONYMS... 3 MODULE 1 TRANSMISSION AND FLUID IDENTIFICATION... 5 TRANSMISSION RANGES... 6 NAG 1 TRANSMISSION MODEL DESIGNATION AND APPLICATION... 8 TRANSMISSION FLUID...10 Oil Level Control...11 TRANSMISSION ID STAMP LOCATION...12 MODULE 2 TRANSMISSION MECHANICAL COMPONENTS, DIAGNOSIS, EVALUATION AND DISASSEMBLY...15 TRANSMISSION DESCRIPTION...15 TRANSMISSION HOUSING...16 VALVE BODY...17 MECHANICAL COMPONENT OVERVIEW...18 Planetary Gear Sets...18 Lubrication of Mechanical Components...19 Clutch Operation and Gear Ratios...20 BRAKES (HOLDING CLUTCHES)...20 B1 Brake...20 B2 Brake...22 B3 Brake...23 B2 and B3 Brake...24 INPUT CLUTCHES...25 K1 Clutch...25 K2 Clutch...27 K3 Clutch...29 OVERRUNNING CLUTCHES...31 PARK LOCK...33 OIL PUMP ASSEMBLY...34 PRELIMINARY DIAGNOSIS...35 TRANSMISSION OIL LEAK DIAGNOSIS...37 Bell Housing and Torque Converter Leak Points...37 Transmission Case Leak Detection Using Dye...37 GEAR TRAIN END PLAY...38 FLUID AND FILTER MAINTENANCE...38 i

3 TRANSMISSION FILTER AND VALVE BODY REMOVAL REQUIREMENTS FLUID AND FILTER ANALYSIS Fluid Type TRANSMISSION HOUSING VALVE BODY Valve, Check Ball and Strainers Solenoid Valves AIR PRESSURE TESTING TORQUE CONVERTER BRAKE (HOLDING) CLUTCHES B2 and B3 Brake Clutches B1 Brake Clutch INPUT CLUTCHES K1, K2 and K3 Input Driving Clutches OVERRUNNING CLUTCHES OIL PUMP PARK LOCK GEAR PLANETARY GEARS IDENTIFICATION AND EVALUATION Pinion, Gears and Carriers MODULE 3 TRANSMISSION POWERFLOW GEAR RATIOS AND CLUTCH APPLICATION FIRST GEAR First Gear Powerflow SECOND GEAR Second Gear Powerflow THIRD GEAR Third Gear Powerflow FOURTH GEAR (DIRECT DRIVE) Fourth Gear Powerflow FIFTH GEAR (OVERDRIVE) Fifth Gear Powerflow REVERSE (NORMAL/STANDARD MODE) Normal Reverse Gear Powerflow REVERSE 1 (4X4 LOW OR WINTER MODE) Reverse 1 Gear Powerflow NEUTRAL (STANDARD MODE) Neutral (Standard Mode) ii

4 NEUTRAL (DEFAULT MODE)...73 Neutral (Default Mode)...74 MODULE 4 MAJOR COMPONENT SERVICE...77 OIL PUMP...77 VALVE BODY...80 Solenoid Valve Testing...81 Valve Identification...82 Valve, Check Ball and Strainers...82 INPUT CLUTCHES...83 K1 Input Clutch...83 K2 Input Clutch...84 K3 Input Clutch...85 BRAKE (HOLDING) CLUTCHES...86 B2 and B3 Brake Clutches...86 B1 Brake Clutch...88 OVERRUNNING CLUTCHES...89 MODULE 5 TRANSMISSION REASSEMBLY...91 REASSEMBLY...91 B2 and B3 Brake Installation...91 Torque Converter Housing, B1 Brake and Oil Pump...91 K1 Input Clutch...91 Input Shaft, Front Annulus and K2 Input Clutch Assembly...92 Output Shaft and Gear Set Assembly, K3 Input and F2 Overrunning Clutches...92 Transmission Housing...92 Gear Train End Play, Output Shaft Bearing and Seal...92 Valve Body and Oil Pan...93 MODULE 6 HYDRAULIC SYSTEM COMPONENTS...95 SYSTEM PRESSURES...95 Line Pressure...95 Modulating Pressure (P-Mod)...97 Shift Pressure...97 Control Valve Pressure...97 Shift Solenoid Valve Pressure...98 Shift Pressure Regulating Pressure...98 Torque Converter Clutch (TCC) Regulating Valve...98 Torque Converter Pressure/Lubricating Pressure...99 iii

5 VALVE BODY SOLENOID VALVES Torque Converter Clutch Solenoid Valve Torque Converter Clutch Off Mode Torque Converter Clutch Modulation Shift Solenoid Valve Shift Pressure Solenoid Valve/Line (Modulating) Pressure Solenoid Valve107 SHIFT GROUPS Shift Group K1/B1 (Gear Change 1 2/4 5) Shift Group K2/K3 (Gear Change 2 3) Shift Group K3/B2 (Gear Change 3 4) SHIFT GROUP SHIFT VALVES Overlap Valve Command Valve Holding Pressure Shift Valve Shift Pressure Shift Valve SHIFT PHASE AND SEQUENCE First-to-Second Shift Sequence (Steady State Drive 1) First-to-Second Shift Transition Second Gear Shifted (Steady State Drive 2) NEUTRAL-TO-DRIVE ENGAGEMENT SHIFT APPLICATION HYDRAULIC SCHEMATICS MODULE 7 ELECTRONIC/ELECTRICAL CONTROL TRANSMISSION CONTROL MODULE (TCM) TCM WIRING DIAGRAMS TCM SIGNALS TCM DIRECT INPUT SIGNALS Automatic Transmission Fluid (ATF) Temperature Sensor P/N Safety Starter Interlock N2 and N3 Input Speed Sensors TCM CAN BUS INPUT SIGNALS ABS Wheel Speed Sensors x4 Low Switch Brake Switch Shift Lever Assembly Shift Lever Positions iv

6 Downshift Safety Cruise Control Engine Management Intervention Electronically Modulated Converter Clutch (EMCC) Operation TCM DIRECT OUTPUT SIGNALS On/Off Shift Solenoid Valves Variable Force Modulating and Shift Pressure Control Solenoid Valves Pulse Width Modulated Torque Converter Clutch Solenoid Valve Solenoid Status in Gear Ranges Solenoid Valve Resistance Values Park/Reverse Interlock Solenoid Starter Interlock TCM CAN BUS OUTPUT SIGNALS VALVE BODY Electric Control Unit/Lead Frame MODULE 8 TROUBLESHOOTING AND DIAGNOSIS NORMAL TRANSMISSION OPERATION (SHIFT PATTERNS) MODULE 9 TRANSMISSION ADAPTATION AND REPAIR VERIFICATION TCM ADAPTATION Driving Style Adaptation Shift Time Adaptation (Shift Overlap, Working Pressure) Fill Pressure Adaptation (Apply Pressure, Modulating Pressure) Fill Time Adaptation (Engagement Time Adaptation) Adaptation Procedure TRANSMISSION REPAIR VERIFICATION TESTING Road Test SPECIAL TOOLS GLOSSARY OF TERMS v

7 Notes: vi

8 INTRODUCTION This course is designed for the technician who has a basic understanding of automatic transmissions. This course covers the New Automatic Gearbox (NAG) 1 (version 1) transmission. Basic operation of this transmission is similar to other transmissions; therefore, this training program focuses on the unique operation, diagnosis and repair of the NAG 1 transmission. The information in this publication should be used with the service information when performing repairs. The concepts learned here will help diagnose and repair this transmission. The NAG 1 transmission is an electronically controlled five-speed automatic transmission with a variably engaged torque converter clutch. It is a conventional automatic transmission because it uses hydraulically applied clutches to shift a planetary gear train, known as clutch-to-clutch control. The electronic components consist of the Transmission Control Module (TCM), Shift Lever Assembly (SLA), an internally mounted valve body with switches, solenoid valves and sensors, and inputs from other vehicle systems. Electronic transmission control provides for more precise adaptation of pressures to corresponding conditions and to the engine output during shifting which results in enhanced shift quality. Electronic control also offers the advantage of a flexible adaptation to various vehicles and engines. Some of the advantages are: Reduced fuel consumption Improved shift comfort Favorable step-up through gear ranges Increased reliability and service life Lower maintenance 1

9 STUDENT LEARNING OBJECTIVES Upon successful completion of this course, you will be able to: Identify the transmission by decoding the ID tag. Identify the proper transmission fluid, service intervals and procedures. Identify all transmission mechanical components. Disassemble, evaluate and inspect the transmission. Demonstrate powerflow. Disassemble and reassemble the transmission subassemblies. Reassemble the transmission. Identify the valve body components. Identify hydraulic flow and solenoid actuation necessary to achieve all gear ratios. Identify all levels of pressure regulation inside the transmission and understand EMCC/TCC operation. Perform the necessary electrical related diagnostic scan tool activities to identify all direct and indirect TCM inputs and outputs. Perform the scan tool shift adaptation procedure. 2

10 ACRONYMS The acronyms listed here are used in this course. ABS Anti-lock Braking System ATF Automatic Transmission Fluid B1 B1 Brake Clutch B2 B2 Brake Clutch B3 B3 Brake Clutch BTSI Brake/Transmission Shift Interlock BUX Built Up for Export CAB Controller Anti-lock Brake CAN Controller Area Network (Bus), Chassis CAN CAN-B Body CAN bus CAN-C Engine and Diagnostic CAN bus C+ C+ CAN Circuit I.D. C C CAN Circuit I.D. CVS Calculated Vehicle Speed DRBIII Diagnostic Readout Box (Third Generation) DMM Digital Multi-Meter DTC Diagnostic Trouble Code ECM Engine Control Module (Diesel Engine Controller) EGS52 Electronic Gearbox System (Version 52) EMCC Electronically Modulated Converter Clutch ESP Electronic Stability Program ETC Electronic Throttle Control F1 F1 Overrunning Clutch F2 F2 Overrunning Clutch K Kinetic K1 K1 Input Clutch K2 K2 Input Clutch K3 K3 Input Clutch 3

11 LED Light Emitting Diode MIL Malfunction Indicator Lamp NAG 1 New Automatic Gearbox (Version 1) NGC Next Generation Controller PCI Programmable Controller Interface (Vehicle Bus System) PCM Powertrain Control Module PWM Pulse Width Modulated SB Service Bulletin SCI Serial Communications Interface (K-Line) SLA Shift Lever Assembly TCC Torque Converter Clutch TCM Transmission Control Module TTS Transmission Temperature Sensor 4

12 MODULE 1 TRANSMISSION AND FLUID IDENTIFICATION Figure 1 NAG 1 Automatic Transmission Clutch Layout The New Automatic Gearbox Version 1 (NAG 1) automatic transmission is an electronically controlled, five-speed transmission equipped with a variably engaged torque converter clutch. As with most automatic transmissions, the NAG 1 transmission uses hydraulically applied clutches to shift a planetary gear train. The NAG 1 automatic transmission has three planetary gear sets. Fifth gear is an overdrive range. The planetary gear set is actuated by application of hydraulic clutches (B1, K1, K2, B3, K3 and B2) via shift valves and electric solenoids in the valve body. The NAG 1 also uses two overrunning clutches (F1 and F2). The Transmission Control Module (TCM) electronically actuates the solenoids. The electronic control system enables application of fluid pressures for adaptation to the current operating conditions such as vehicle speed and engine output during a shift phase, thus providing quality shifts. The system performs its functions based on continuous sensor and switch feedback information. In addition, the TCM receives information from the engine management, body control and chassis control systems over the CAN bus. 5

13 The TCM controls fluid pressures to the operating clutches during the shift phase by looking at two input speed sensors (N3 and N2) (calculated input shaft speed) and ABS wheel speed sensors (calculated output shaft speed) along with other various inputs. TCM control provides quality transmission shifting. Having more precise control over the hydraulic system provides the advantage of flexible adaptation to various vehicle and engine combinations. The NAG 1 automatic transmission provides: Five forward gears Adaptive mode Close ratios (1st through 5th) Fill-for-life fluid (some versions have lengthy fluid change intervals) Two reverse gears TRANSMISSION RANGES Figure 2 Crossfire Shift Lever Assembly Shown 6

14 The shift lever can be moved into various positions. The shift lever position and gear selections are: Table 1 Transmission Ranges SHIFT LEVER POSITION P R N D GEAR SELECTION DESCRIPTION Parking and starting position. Reverse gear (standard and winter mode). Neutral and starting position. No transmission of power takes place. The vehicle can be moved freely. Allows starting engine with vehicle in motion. All five forward gears are available. 4 Upshifting only to 4th gear range. Provides engine braking. Inhibits overdrive. 3 Upshifting only to 3rd gear range. Provides engine braking. 2 Upshifting only to 2nd gear range. Provides engine braking. 1 Driving possible only in 1st gear range. Provides maximum engine braking. GEAR RANGE Table 2 Gear Range Ratios RATIO (W5A580, W5J400 AND W5A380) RATIO (W5A330) 1st nd rd th th Reverse Reverse 1 (4WD/AWD position on LX and WK) (Winter Mode Crossfire Only)

15 A Winter/Standard (W/S) switch is incorporated into the shift lever assembly on Crossfire vehicles. With the W/S switch in the S position, lower gear ratios are provided in first and reverse gears. With the W/S switch in the W position, higher ratios are provided in first and reverse gears. NAG 1 TRANSMISSION MODEL DESIGNATION AND APPLICATION The following illustration provides an example explanation of the NAG 1 transmission model designation. W Hydraulic Torque Converter A or J 5 Number of Forward Gears 580, 380 or 330 Figure 3 Model Designation Explanation Automatic or Jeep Four Wheel Drive Maximum Input Torque (N m) 722. Automatic Transmission for Passenger Cars 6. Sales Designation (W5AXXX) 81 Version of Transmission for Vehicle Application Matched to Engine (Digits Vary with Application) Figure 4 Model Designation Explanation (Sprinter/Crossfire) 8

16 The NAG 1 family of five-speed automatic transmissions includes the W5A580, the W5J400, the W5A380 and the W5A330 versions. The acronym NAG comes from the German words for new automatic transmission. The 1 refers to the first iteration of the transmission. Table 3 Family of NAG 1 Transmissions MODEL YEAR MARKET VEHICLE FAMILY ENGINE APPLICATION SALES CODE TRANSMISSION SALES CODE SALES CODE DESCRIPTION 2003 BUX U.S. Grand Cherokee (WG) Sprinter (VA) 2.7L 5-Cyl. Diesel (ENF) 2.7L 5-Cyl. Diesel (EX9) DGJ DGJ Five-Speed Auto Transmission (W5J400) Five-Speed Auto Transmission (W5A380) 2004 U.S. U.S., Canada, Mexico and BUX Sprinter (VA) Crossfire (ZH) 2.7L 5-Cyl. Diesel (EX9) 3.2L 6-Cyl. Gas (EGX) DGJ DGU Five-Speed Auto Transmission (W5A380) Five-Speed Auto Transmission (W5A330) U.S. Sprinter (VA) 2.7L 5-Cyl. Diesel (EX9) DGJ Five-Speed Auto Transmission (W5A380) U.S., Canada, Mexico and BUX Chrysler 300C and Dodge Magnum (LX) 5.7L 8-Cyl. Gas (EZB) DGJ Five-Speed Auto Transmission (W5A580) 2005 U.S., Canada and Mexico Grand Cherokee (WK) 3.7L 6-Cyl. Gas (EKG) DGJ Five-Speed Auto Transmission (W5A580) BUX Grand Cherokee (WH) 3.7L 6-Cyl. Gas (EKG) or 3.0L 6-Cyl. Diesel (EXL) DGJ Five-Speed Auto Transmission (W5A580 or W5J400) U.S., Canada, Mexico and BUX Crossfire (ZH) 3.2L 6-Cyl. Gas (EGX) DGU Five-Speed Auto Transmission (W5A330) 9

17 TRANSMISSION FLUID Transmission fluid serves a number of purposes including application of hydraulics, lubrication, cooling, cleaning and seal conditioning. Transmission shift quality, heat dissipation and Transmission Control Module (TCM) calibration all dictate the type of transmission fluid that is used. Transmission fluids are similar but have different characteristics such as viscosity and the additives in the fluid, which is why there will be different fluids used in Crossfire, Sprinter and 300C. Drain and refill the transmission fluid at the recommended service intervals. The transmission has varying capacities depending on vehicle application. Transmission fluid capacity includes the transmission, the torque converter and the transmission fluid cooler. The transmission is supplied from the plant with the proper amount of fluid. The fill tube in Sprinter and Crossfire vehicles is sealed from the factory and requires a special service dipstick tool (#8863A) to check fluid level and a special cap is used for sealing the transmission dipstick tube. A special funnel (#8908) which has a filter, is required in Europe to fill the transmission. This allows reusing the transmission fluid after being filtered through the funnel. The 300C (LX) requires special service dipstick tool (9336). Grand Cherokee (WJ) comes equipped with a dipstick. 1 Locking Pin 3 Fill Tube 2 Fill Tube Cap Figure 5 Fill Tube Cap (Sprinter/Crossfire) The transmission fluid can be checked in either Park or Neutral. Refer to the appropriate Owner s Manual and service information for fluid level checking, service intervals, fill procedures, fluid capacity, fluid application and type. 10

18 Oil Level Control 1 Float 2 Oil Return Path Figure 6 Oil Level Control Float on Valve Body LTD407a The oil level control float closes the opening between the oil pan (sump) and the planetary gear set chamber so that the gear sets do not become overfilled and churn in the oil. As the oil level rises due to normal operating temperature increase, the oil forces a float on the valve body to rise against an opening in the housing that leads to the gear set chamber. The float prevents the oil from entering the transmission gears which can cause oil foaming (aeration). Instead, the oil in the sump rises up around the outside of the gear set chamber. Cast drain ports in the gear set chamber area allow for excess oil return to the sump (oil pan). 11

19 TRANSMISSION ID STAMP LOCATION 1 Transmission Bar Code Identification Label 2 Pin Stamp Pad Figure 7 Transmission Bar Code Label and Pin Stamp Pad Location 12

20 1 Traceability 7 Build Sequence 2 Supplier Code 8 Last Three Part Number Digits 3 Component Code 9 Revision Level 4 Build Day (Julian Date) 10 Transmission Part Number 5 Build Year 11 Part Number Prefix 6 Line/Shift Code Figure 8 Example Transmission Bar Code Label Interpretation 13

21 Notes: 14

22 MODULE 2 TRANSMISSION MECHANICAL COMPONENTS, DIAGNOSIS, EVALUATION AND DISASSEMBLY 1 B1 Brake 5 K3 Clutch 2 K1 Clutch 6 B2 Brake 3 K2 Clutch 7 F2 Overrunning Clutch 4 B3 Brake 8 F1 Overrunning Clutch Figure 9 NAG 1 Gear Set and Shift Members TRANSMISSION DESCRIPTION The NAG 1 automatic transmission is an electronically controlled five-speed with a variable slip rate clutch in the torque converter. Three planetary gear sets provide the five forward speeds plus two reverse speeds only when you have AWD on a 300C or 4x4 on a Jeep Grand Cherokee or Crossfire with a Winter/Standard Mode switch. The gears are actuated by a combination of electrical and hydraulic components. The gear ranges are shifted by an appropriate combination of three multi-disc holding clutches, three multi-disc input (driving) clutches and two sprag-type overrunning clutches. 15

23 TRANSMISSION HOUSING The torque converter housing and transmission housing are made of light aluminum alloy. The housings are bolted together and joined (centered) at the outer brake carrier of the B1 brake. A coated intermediate metal shim serves as a gasket between the two housings. The oil pump is bolted to the torque converter (bell) housing and to the outer brake carrier of the B1 brake, which is covered by the transmission housing. The oil pump is secured by several bolts from the inside of the transmission and transmission disassembly is required to service the pump. The stator support shaft is pressed and splined to the B1 brake outer carrier. The valve body assembly is bolted to the lower portion of the transmission housing. 16

24 VALVE BODY The valve body assembly incorporates shift and pressure regulation valving for hydraulic control, and an electrical control unit (lead frame) secured to the top of the valve body. The electrical control unit is basically a lead frame that houses the conducting bars to provide connection for electrical components such as the input speed sensors, shift solenoids and regulation solenoids. The lead frame also incorporates a 13-pin plug for connection to the vehicle wiring harness and the Transmission Control Module (TCM). A sealed plastic extension for the 13-pin plug prevents fluid loss through the opening in the transmission housing and must be removed prior to transmission or valve body removal. 1 Heat Shield 7 Bolt 2 Valve Body Assembly 8 Drain Plug (If Equipped) 3 Valve Body Retaining Bolt 9 Drain Plug Gasket (If Equipped) 4 Oil Filter Pin Harness Connector 5 Oil Pan 11 Guide Bushing Retaining Bolt 6 Clamping Element 12 Guide Bushing (Extension to Valve Body Plug) Figure 10 Valve Body Assembly 17

25 MECHANICAL COMPONENT OVERVIEW Planetary Gear Sets The transmission consists of an input shaft (Fig. 11), an output shaft, a sun gear shaft and three integrated planetary gear sets (Fig. 12). The higher torque capacity versions of the NAG 1 transmission are equipped with four pinion carriers in the planetary gear sets. The front and rear planetary carriers on lower torque-rated transmissions are equipped with three pinions each. 1 K1 Inner Disc Carrier with Integrated Front Planetary Carrier 2 Thrust Bearing 3 Input Shaft with Front Annulus and K2 Clutch Assembly Figure 11 Input Shaft and Front Gear Set 18

26 1 Teflon Seal Rings 7 K3 Clutch Assembly 2 Output Shaft and Center Planetary Carrier 8 Thrust Washer 3 Needle Bearing 9 Thrust Bearing 4 Thrust Washer 10 Shim 5 Rear Planetary Carrier and Center Annulus 6 Center Sun Gear/Hollow Shaft, Rear Sun Gear and F2 Overrunning Clutch 11 Snap Ring Figure 12 Output Shaft with Center and Rear Planetary Gear Sets Lubrication of Mechanical Components The oil flow and pressure for the Torque Converter Clutch (TCC) and the K2 clutch are supplied through bores in the input shaft. The oil flow and pressure for the K3 clutch are routed through the output shaft. Also, both shafts are bored for lubricating oil to internal components. All bearings, planetary gear sets, overrunning clutches and driving (input) clutches are supplied with oil for lubrication. 19

27 Clutch Operation and Gear Ratios Applying or releasing one or more of the three input clutches and three brake clutches hydraulically actuates the gear range selected. The F1 and F2 overrunning clutch assemblies also are required to obtain the appropriate gear range. The TCM controls the hydraulic circuits through the actuation of solenoids within the transmission. The TCM controls accurate pressure application under all driving conditions which results in quality shifting. BRAKES (HOLDING CLUTCHES) Brake (holding clutch) assemblies used in the NAG 1 transmission are all friction clutches anchored to the transmission case. Brake assemblies are used to hold and prevent rotation of specific components of the three planetary gear sets to transmit drive torque. B1 Brake The B1 Brake is mounted on the torque converter housing toward the front of the transmission. The F1 clutch is located and mounted in the K1 clutch hub/front sun gear shell assembly. The front sun gear is attached to the K1 clutch hub/front sun gear shell assembly. The B1 clutch consists of four OD splined single-sided friction discs and four ID splined single-sided friction discs. 1 B1 Brake 3 F1 Overrunning Clutch 2 Front Sun Gear Shell 4 Front Sun Gear (Hidden) Figure 13 B1 Brake LTD401 20

28 1 B1 Clutch Outer Hub (with Reaction Shaft Support) 6 Multiple Disc Pack 2 B1 Clutch Piston 7 Snap Ring 3 Disc Spring 8 Multi-Use Spring Compressor (8900) 4 Snap Ring A B1 Clutch Port (Apply Air to Remove Piston) 5 Disc Spring Figure 14 B1 Brake Components 21

29 B2 Brake 1 B2 Brake 3 F2 Overrunning Clutch 2 Center and Rear Sun Gear Assembly Figure 15 B2 Brake 4 K3 Clutch Shell The B2 brake is located at the rear of the transmission and houses four double-sided friction discs and four steel discs. 22

30 B3 Brake 1 B3 Brake 2 Rear Carrier and Center Annulus Gear Assembly Figure 16 B3 Brake The B3 brake is located in front of the B2 brake at the rear of the case. The B3 brake disc pack is comprised of five double-sided friction discs and five steel discs. LTD403 23

31 B2 and B3 Brake 1 Snap Ring (Selective) 9 B3 Piston Sealing Ring 2 Multi-Disc Pack 10 B2 Piston 3 Disc Spring (Belleville) 11 Piston Guide Sealing Ring 4 B2 and B3 Piston Guide 12 Piston Guide Sealing Ring 5 O-Ring 13 Piston Guide 6 B3 Piston Sealing Ring (Outer) 14 Piston Back Pressure Disc Spring 7 B3 Piston Sealing Ring (Inner) 15 Spring Plate 8 B3 Piston and B2 Outer Disc Carrier 16 Snap Ring Figure 17 B2 and B3 Brake Components 24

32 INPUT CLUTCHES The input clutch assemblies are used to drive the planetary gear set components by connecting them to a rotating component, such as an input shaft or another planetary member. The NAG 1 transmission employs three input driving clutch assemblies: K1 clutch K2 clutch K3 clutch K1 Clutch 1 K1 Clutch Hub/Front Sun Gear Shell 25 3 K1 Clutch 2 Front Planetary Carrier 4 F1 Overrunning Clutch Figure 18 K1 Clutch The K1 clutch is located directly behind the B1 brake. The K1 clutch consists of six OD splined single-sided friction discs and six ID splined single-sided friction discs. The K1 input clutch assembly (and front sun gear) rests on the B1 brake assembly. As with any clutch assembly, the K1 clutch incorporates friction and steel discs, a piston, piston spring, seals, O-rings and snap rings. In the NAG1 transmission, the K1 clutch also includes the F1 overrunning clutch.

33 The K1 clutch hub/front sun gear shell houses the K1 clutch and the F1 clutch (inside front sun gear). The K1 clutch uses a piston and Belleville spring to achieve proper engagement and disengagement of the clutch assembly. 1 K1 Clutch Hub/ Front Sun Gear Shell 7 Disc Spring 2 F1 Overrunning Clutch 8 Spring Plate 3 Snap Ring 9 Spring Plate Sealing Ring 4 Outer Disc Carrier Sealing Ring 10 Snap Ring 5 Piston Sealing Ring 11 Snap Ring 6 Piston 12 Multi-Disc Pack Figure 19 K1 Clutch Assembly 26

34 K2 Clutch Rear Carrier and Center Annulus Gear Assembly 2 K2 Clutch Figure 20 K2 Clutch The K2 clutch is located behind the K1 clutch assembly and is housed with the input shaft and front annulus gear assembly. The K2 clutch pack contains six doublesided friction discs and six steel discs. LTD405 27

35 The K2 clutch is shown with the input shaft and front annulus along with the K1 clutch inner disc carrier and integrated front planetary carrier. 1 K1 Inner Disc Carrier with Integrated Front Planetary Carrier 9 Spring Retainer 2 Thrust Bearing 10 Snap Ring 3 Input Shaft with Front Annulus and K2 Clutch Assembly 11 Disc Spring 4 Piston Outer Sealing Ring 12 Multi-Disc Pack 5 Piston Inner Sealing Ring 13 Snap Ring 6 Piston 14 Rear Annulus Gear 7 Disc Spring 15 Snap Ring 8 Spring Retainer Seal Figure 21 K2 Clutch Assembly 28

36 K3 Clutch Center Sun Gear 3 K3 Clutch 2 Rear Sun Gear Figure 22 K3 Clutch The K3 clutch is the rearward most input clutch situated inside and between the B3 brake and B2 brake. The K3 clutch pack consists of five OD single-sided friction discs and five ID single-sided friction discs. LTD406 29

37 The K3 clutch is shown with internal components. 1 Snap Ring 6 Piston 2 Multi-Disc Pack 7 Piston Sealing Ring 3 Spring Plate 8 K3 Clutch Shell 4 Snap Ring 9 Multi-Use Spring Compressor (8900) 5 Disc Spring Figure 23 K3 Clutch Assembly 30

38 OVERRUNNING CLUTCHES The F1 and F2 sprag-type overrunning clutches are incorporated into the transmission to help optimize shift quality. The front F1 overrunning clutch is supported on the extension of the stator shaft (B1 brake hub) inside the front sun gear. The rear F2 overrunning clutch (shown below) is located between the center sun gear (hollow shaft) and the rear sun gear. 1 Center Sun Gear/Hollow Shaft 5 Snap Ring 2 Retaining Ring 6 O-Ring (Two Used) 3 F2 Overrunning Clutch 7 Brass End Faces Out (Toward Oil Pump) When Installed 4 K3 Clutch Inner Disc Carrier (Hub) Figure 24 F2 Overrunning Clutch 31

39 The overrunning clutch optimizes individual gear shifts. The clutches lock the individual elements of a planetary gear set together or to the transmission housing in one direction of rotation, causing torque to be transmitted. When the inner race of the overrunning clutch is locked and the outer race turns counterclockwise, the sprag-type locking elements adopt a diagonal position to allow overrunning. The outer race slides over the sprags with minimal friction. When the rotation of the outer race changes to a clockwise direction, the sprag elements, due to design contour, stand up and lock the outer race and inner race together. This effectively holds or drives a member of the planetary gear set. 1 Counterclockwise 5 Gear 2 Clockwise 6 Cage 3 Sprag-Type Locking Element 7 Inner Race 4 Outer Race Figure 25 Sprag-Type Overrunning Clutch 32

40 PARK LOCK 1 Park Lock Gear 5 Guide 2 Park Lock Pawl 6 Detent Plate 3 Guide Bushing 7 Spring Assembly 4 Park Lock Connecting Rod 8 Cone Figure 26 Park Lock The park lock prevents the vehicle from rolling by locking the output shaft to the case. Placing the shift lever in the Park position engages the park lock. The park lock assembly consists of a park lock gear, park lock pawl, taper with spring assembly and a guide. Engaging the park lock moves the taper between the lock pawl and the guide, forcing the pawl to engage the park lock gear. The park lock assembly is located on the transmission output shaft and locks the shaft to the case. LTD468 33

41 OIL PUMP ASSEMBLY 1 B1 Brake Retainer Bolt 4 Oil Pump Retaining Bolt 2 Torque Converter Housing 5 B1 Brake (Holding Clutch) 3 Intermediate Plate 6 Oil Pump Assembly Figure 27 Oil Pump Assembly The oil pump assembly supplies fluid under pressure to the transmission hydraulic circuits and to the torque converter. The version of the gear pump used in the NAG 1 transmission is called a crescent gear pump. The crescent gear pump consists of an externally toothed gear that meshes with an internally toothed gear inside the pump housing. The inner gear, driven by the engine through lugs on the rear of the torque converter, drives the outer gear. A crescent-shaped piece extends into the pumping chamber and lies between the two gears. The crescent separates the inlet and outlet ports. As the gears rotate, the clearance increases at the inlet port, creating the low pressure that allows atmospheric pressure to push in the fluid. The gear teeth carry the fluid to the outlet port to discharge the fluid under pressure. The oil pump is mounted in the transmission converter housing. The oil pump can only be serviced by disassembling the transmission. The bolts securing the oil pump to the housing are inside the transmission through the B1 brake assembly. 34

42 PRELIMINARY DIAGNOSIS The technician should always verify questions related to the concern. The following are examples of some questions that should be answered when diagnosing a shift concern: When put into gear, is there any delay before engagement? What do the shifts feel like? Are the shifts smooth without delay? Does the engine flare up between gears? Is each gear range achieved? Did the shift occur at the correct road speed? Road testing is an important part of the diagnostic process and must not be overlooked. Drive the vehicle under the same circumstances that the customer indicated the concern occurred. If the problem occurs when the transmission is cold, the road test should be performed under these same circumstances. Before road testing, the transmission should be inspected for leaks or damage, and all linkage adjustments should be checked and corrected if necessary. When on the road test, be sure to shift the transmission into all gear positions to verify that the transmission shifts the way that it is suppose to shift. This will help to determine if what the customer feels is proper operation. A visual inspection should also be performed. Check all associated wiring, including harnesses and connectors. Look for fluid leaks, external damage, and in some cases, remove the input and output speed sensors to inspect for metal filings on the magnet. If metal filings are present on the input or output speed sensor magnet, an internal component may be failing. Contaminated or burnt fluid could be caused by an internal failure. All of these inspections and checks must be performed before the transmission is removed from the vehicle. Line pressure readings cannot be directly measured. However, calculated oil pressure for line pressure regulation and shift pressure regulation can be viewed by using the diagnostic scan tool. Fluid condition, fluid level and checking all connections are all very important in diagnosing transmission problems and must be performed before the transmission is removed from the vehicle. 35

43 Symptom-based diagnostics are an essential part of diagnosing the transmission from preliminary diagnosis to road testing, which includes isolating and repairing the fault. Diagnostic worksheets have been developed to aid in isolating and identifying the fault. Note: It is important during any diagnosis to follow DaimlerChrysler s Six-Step Troubleshooting procedure in addition to specific procedures for correcting electronic transmission problems. Verify the customer concern. Determine related symptoms. Analyze the symptoms. Isolate the problem. Repair the problem. Verify proper operation. Section two of the check sheet is to be completed by the person making the actual repair. By following all the steps outlined in the worksheet, you are not only following a repair path that should isolate the problem, but you are also keeping in line with the troubleshooting process. Verify the customer concern. Perform a visual inspection. Check the SBs. Perform a shift lever test. Read the DTCs. Flash, if necessary. Perform a verification test. 36

44 TRANSMISSION OIL LEAK DIAGNOSIS Bell Housing and Torque Converter Leak Points Possible sources of leaks at the bell housing are: If the converter is wet, it is likely a weld seam joint around the outside diameter or hub weld leak. Oil pump leaks can be at the front seal. Leak at the 13-pin connector. Transmission Case Leak Detection Using Dye Begin with a thorough visual inspection of the transmission, particularly at the area of the suspected leak. If a fluid leak source is not readily identifiable, use the following steps listed below: 1. Do not clean or degrease the transmission at this time because some solvents can cause rubber to swell, temporarily stopping the leak. 2. Add a Mopar -approved dye to the transmission fluid. Lift the drive wheels off the ground, start the engine and let the engine idle to rotate the driveshaft. Allow the engine to idle for 15 minutes. Check the transmission dipstick to make sure the dye is thoroughly mixed as indicated with a bright yellow color under a black light. 3. Using a black light, inspect the entire transmission for fluorescent dye, particularly at the suspected area of the oil leak. Look for the dye in the oil. If the oil leak is found and identified, repair as necessary. 4. If dye is not observed, drive the vehicle at various speeds for approximately 24 km (15 miles), and repeat the inspection. 37

45 GEAR TRAIN END PLAY Gear train end play is a very critical pre-disassembly check to help determine the condition of the transmission. End play readings greater than specification (larger gap) indicate that a bearing or thrust plate is either missing, worn or has disintegrated, in which case there will be debris in the oil pan. End play readings that are below specification (smaller gap) indicate that a bearing is out of position or that the transmission might have been previously set-up incorrectly. Block and support the transmission in a vertical position. Attach the tools as shown to measure end play. The gear train end play is measured differently when the transmission is being reassembled. Measure the end play between the park pawl gear and the end of the housing and between the rear of the bearing contact surface and the end of the housing. The difference between the two measurements is the gear train end play. Select the appropriate shim so that the end play is between mm ( in.). 1 Tool (Part of Set) 3 Tool C Tool Figure 28 Gear Train End Play FLUID AND FILTER MAINTENANCE Refer to the vehicle Owners Manual or service information for the appropriate maintenance schedules. 38

46 TRANSMISSION FILTER AND VALVE BODY REMOVAL REQUIREMENTS The transmission oil filter incorporates a plastic filter neck that connects the filter to the valve body. It is important that the oil filter neck is properly installed through the valve body seal in the valve body. 1 Valve Body 3 Oil Filter 2 Oil Pan 4 Filter Neck Figure 29 Valve Body Assembly with Filter Removing the valve body requires removal of the oil pan. Also on the NAG 1 transmission, the guide bushing (extension between the transmission harness connector and electro-hydraulic/lead frame unit 13-pin connector) must be removed. Disconnect the transmission harness connector by rotating the bayonet lock of the guide bushing. Loosen and pull out the guide bushing. The guide bushing also seals against the housing to prevent oil from leaking. The guide bushing or electrical connection on the valve body can break if the bushing is not removed prior to valve body removal. FLUID AND FILTER ANALYSIS During transmission failure analysis, the oil pan and filter provide key information that should be examined very carefully. As the oil pan is being drained, collect a portion of the fluid for analysis. Does the fluid show any signs of contamination or additives? Does the fluid show any signs of aeration? 39

47 After the oil pan is removed, inspect the oil filter for the following: Is the oil filter neck cracked or improperly installed? Cracks in the plastic housing and neck or a poor fit between the seal and the neck can allow air to enter the oil pump and aerate the fluid. Is the filter contaminated with debris? 1. If the debris appears to contain fibers, it is likely from the clutch discs. 2. If the debris appears to contain metal, it is likely from the thrust plates or steel from the roller or thrust bearings. 3. If the debris appears to contain rubber/teflon, it is likely originating in the valve body or clutch piston seals. Careful examination of the pan and filter can reveal clues to conditions that the transmission is experiencing that the Diagnostic Scan Tool might not indicate. Debris, contamination or aeration can all cause insufficient oil pressure in the transmission leading to premature transmission failure. For Shell 3403 oil, a pure brown or black coloring had neither an influence to the coefficient of friction nor to any other characteristics of the oil. The color of the oil is no reason for a complaint. Burnt smelling oil indicates slipping clutch disc assemblies. Replace the appropriate components and the oil and filter. When the oil has graphite-mud type abrasions in it, or there are 1 mm or larger chips in the oil pan, mechanical damage has occurred in the transmission. Based on the complaint, replace the corresponding components or the transmission as necessary. When a repair is possible, the transmission, oil cooler and lines must be cleaned and flushed and the oil and filter replaced. Fluid Type Mopar ATF+4 (Type 9602) Automatic Transmission Fluid is the recommended transmission fluid when servicing the NAG 1 transmission used in domestic version transmissions. Using ATF+4 ensures optimum transmission performance. The prescribed fluid level must be maintained. Shell 3403 must be used in Sprinter, Crossfire and Mercedes Benz versions of the NAG 1 transmission. The transmission is calibrated to use Shell 3403 fluid, rather than ATF+4. 40

48 TRANSMISSION HOUSING The torque converter (bell) housing and transmission housing (case) are made from a light alloy. The two housings are bolted together and centered by the outer disc carrier of the B1 brake (holding clutch). A coated intermediate plate provides sealing between the housings. Both the B1 clutch and the oil pump are bolted to the torque converter housing. The stator shaft is pressed into the B1 clutch outer retainer and prevented from rotating by splines. The valve body is in the conventional location and secured to the transmission case. The oil pan seals the closure and provides an oil sump. The NAG 1 transmission is unusual in that after removing the oil pan and valve body, the transmission is placed on the bell housing and the transmission housing is unbolted and lifted off the torque converter housing. As the housing is lifted off, the internal components are left resting on the torque converter housing. Caution: The rear output shaft bearing must be removed using special tools before lifting the transmission housing from the torque converter housing. If the bearing is left in place when removing the transmission housing, a portion of the internal components can be lifted off with the housing and potentially fall from the housing causing personal injury and/or damage to the transmission. 41

49 VALVE BODY Use a speed wrench while removing the valve body-to-case bolts. This is done to ensure the bolts have not lost the required torque. Loss of torque on a bolt can allow transmission fluid to leak into an adjacent passageway and cause the transmission to go into Limp-In Mode or cause a poor or late shift. After the valve body removal, inspect the seals, gaskets and valve body-to-case surfaces for damage. 1 Heat Shield 7 Bolt 2 Valve Body Assembly 8 Drain Plug (If Equipped) 3 Valve Body Retaining Bolt 9 Drain Plug Gasket (If Equipped) 4 Oil Filter Pin Harness Connector 5 Oil Pan 11 Guide Bushing Retaining Bolt 6 Clamping Element 12 Guide Bushing (Extension-to-Valve Body Connector) Figure 30 Valve Body Assembly 42

50 Valve, Check Ball and Strainers The 12 check balls (eight steel and four plastic) used in the NAG 1 transmission are located in the cast pockets in the underside of the valve body just below the separator plate. Check balls need to be inspected very carefully for creases or irregularities. Slight irregularities on a check ball can cause intermittent problems. Remove and install the valve body with the separator plate and transfer plate attached, to prevent the check balls from falling out of the cast pockets in the valve body. It is very important in diagnosis to know which check ball came from which pocket. Use the hydraulic flow diagrams in the service information to determine which gears are affected by a particular leaking check ball. Also, note the positions of any strainers associated with the solenoid valves. The strainers are located in both halves of the valve body. 1 Steel Check Balls 4 Pressure Feed Valve 2 Central Strainer 5 Plain Dowel Pin 3 Plastic Check Balls 6 TCC Solenoid Valve Strainer Figure 31 Valve Body Check Ball and Strainer Locations Note: During reassembly, check balls should only be retained using Vaseline or Trans-Jel. DO NOT use inappropriate greases (such as wheel bearing or white lithium grease). LTD502 43

51 Solenoid Valves The solenoid valves are located in the upper valve body connected to the lead frame which provides electrical connection to the 13-pin connector. The solenoid valves are sealed to the valve body using O-rings. A strainer is located under each solenoid valve to protect the valve from contamination. 1 Solenoid Valve Cap Shift Solenoid Valve 2 Solenoid Valve Cap 9 TCC Solenoid Valve 3 Bolt (M6X32) /4 5 Shift Solenoid Valve 4 Bolt (M6X30) Shift Solenoid Valve 5 Leaf Spring 12 Lead Frame 6 Modulating Pressure Solenoid Valve 7 Shift Pressure Regulating Solenoid Valve 13 Upper Valve Body (Shift Plate) Figure 32 Solenoid Valve Locations 44

52 AIR PRESSURE TESTING Using controlled regulated air pressure instead of fluid pressure, the clutch pistons can be tested for large leaks by listening for the sound of air escaping past a piston seal if the seal is leaking. By removing the valve body and using the appropriate port, each clutch piston can be actuated. While applying air pressure to the port, the piston moves and compresses the clutch pack. If a seal is leaking, air is heard leaking past the piston. Testing can be done with the transmission in the vehicle or on the work bench. Perform the following steps when air pressure testing the clutches: Remove the transmission oil pan and valve body. Apply air pressure to the ports one at a time. Note: The compressed air supply must be free of all dirt and moisture. Use a pressure no greater than 30 psi. Note: Listen for the clutch to apply (heard as a slight thud sound). If a large amount of air is heard escaping, the transmission must be removed from the vehicle, disassembled and all seals inspected. Each clutch includes a bleed orifice and so a small amount of air leakage is normal. 45

53 1 K1 Clutch Apply Port 5 B3 Clutch Apply Port 2 B1 Clutch Apply Port 6 B2 Clutch Counter-Pressure Port (Do Not Air Test This Port) 3 K2 Clutch Apply Port 7 K3 Clutch Port 4 Torque Converter Clutch Apply Port 8 B2 Clutch Apply Port Figure 33 Clutch Pressure Ports 46

54 TORQUE CONVERTER The Torque Converter Clutch (TCC) is hydraulically operated and electronically controlled. The TCC consists of a piston and friction discs that provide a mechanical link between the impeller and turbine. When pressure is applied to the rear of the TCC piston, TCC engagement is obtained. The NAG 1 torque converter clutch is never fully engaged. The TCC when engaged, is always slipping at a rate of somewhere between 5% and 95%. This reduces excess heat build-up, engine vibration and pulse transmission through the torque converter and improves fuel economy. TCC operation can be activated in 5th, 4th or 3rd gear ranges, depending on transmission model, application, shift lever position, transmission temperature and other factors. The hub of the torque converter housing drives the transmission oil pump at engine speed. Caution: The torque converter must be replaced if a transmission failure resulted in large amounts of metal or fiber contamination in the fluid. 1 Turbine 6 Torque Converter Clutch Piston 2 Impeller 7 Torque Converter Cover (Shell) 3 Stator 8 Internal-Toothed Disc Carrier 4 Input Shaft 9 Clutch Disc Set 5 Reaction Shaft/Stator Support 10 External-Toothed Disc Carrier Figure 34 Torque Converter 47

55 BRAKE (HOLDING) CLUTCHES B2 and B3 Brake Clutches The B2 and B3 brake clutches are removed along with the transmission housing. With the case horizontal, remove the snap ring (selective) retaining the B3 brake clutch components. Remove the B3 clutch discs and reaction plate. Remember to tag the clutch components for reassembly. The B3 piston is also the B2 outer disc carrier. To remove the B2 clutch and components, remove the two retaining bolts located in the rear valve body area of the case. 1 Snap Ring 9 B3 Piston Sealing Ring 2 Multiple Disc Pack 10 B2 Piston 3 Disc Spring (Belleville) 11 Piston Guide Sealing Ring 4 B2 and B3 Piston Guide 12 Piston Guide Sealing Ring 5 O-Ring 13 Piston Guide 6 B3 Piston Sealing Ring (Outer) 14 Piston Back Pressure Disc Spring 7 B3 Piston Sealing Ring (Inner) 15 Spring Plate 8 B3 Piston and B2 Outer Disc Carrier 16 Snap Ring Figure 35 B2 and B3 Brake Clutch Components 48

56 B1 Brake Clutch The B1 brake clutch assembly is secured to the torque converter housing from the outside with 11 bolts. The oil pump assembly is retained from the inside through the B1 brake. Remove the oil pump bolts to remove both the oil pump and the B1 brake assembly. With the B1 brake assembly removed, the separator plate can be lifted from the torque converter housing. Special tools are used to disassemble the B1 brake. With the B1 brake selective snap ring, disc pack and spring removed, a multiple use spring compressor (8900) is used to remove the B1 piston snap ring. Remove the spring and then, blow the piston out using 20 psi air pressure at the port (A) shown. 1 B1 Clutch Outer Hub (With Reaction Shaft Support) 6 Multiple Disc Pack 2 B1 Clutch Piston 7 Snap Ring 3 Disc Spring 8 Multiple-Use Spring Compressor (8900) 4 Snap Ring A B1 Clutch Port (Apply Air to Remove Piston) 5 Disc Spring Figure 36 B1 Brake Clutch Components 49

57 INPUT CLUTCHES K1, K2 and K3 Input Driving Clutches The input clutch and gear set assemblies are stacked on top of each other when the transmission is resting on the torque converter housing. The first to be removed is the output shaft, center and rear planetary gear sets and the K3 input clutch. The K2 input clutch, front planetary gear set and the input shaft come next. The K1 input clutch assembly (and front sun gear) rests on the B1 brake assembly. Remove the components one by one. Note the orientation and positions of any thrust bearing and thrust washers. 1 K1 Clutch 5 Thrust Washer 2 K1 Clutch Hub/Front Sun Gear Shell 3 K3 Clutch, Output Shaft, Center and Rear Planetary Gear Sets 4 Thrust Bearing 6 K2 Clutch, Front Planetary Gear Set and Input Driving Shaft 7 Teflon Sealing Rings Figure 37 Input Clutches K1, K2 and K3 and Gear Set Components 50

58 OVERRUNNING CLUTCHES The overrunning clutches F1 and F2 are installed in the front planetary gear set between the sun gear and the reaction shaft (F1) and between the rear planetary gear set sun gear (F2) and center planetary gear set sun gear through the hollow shaft. The overrunning clutches either lock two gear set components together or hold components to the case. When removing these clutches, note their orientation and position for reassembly purposes. These clutches can be removed as assemblies. 1 Hollow Shaft 5 Snap Ring 2 Retainer Ring 6 O-Rings (2) 3 F2 Overrunning Clutch 7 Brass End Faces Out (Toward Oil Pump) When Installed 4 K3 Clutch Inner Disc Carrier and Rear Planetary Sun Gear Figure 38 F2 Overrunning Clutch Location 51

59 OIL PUMP The oil pump is a gear-type pump (with a half-moon crescent between the inner and outer gears). The oil pump delivers the same amount of fluid with each revolution regardless of rotation speed and is referred to as a positive displacement pump. As oil pump speed increases, oil pump volume increases. The flange (hub) on the torque converter drives the inner gear of the oil pump. So effectively, when the engine is running, the oil pump is running (via the torque converter). The oil pump is mounted in the transmission converter housing. This oil pump can only be serviced by disassembling the transmission. The bolts securing the oil pump to the housing are inside the transmission through the B1 brake assembly. A dowel pin in the B1 brake assembly aligns the B1 brake and intermediate plate to the torque converter housing. 1 B1 Brake Retainer Bolt 4 Oil Pump Retaining Bolt 2 Torque Converter Housing 5 B1 Brake (Holding Clutch) 3 Intermediate Plate 6 Oil Pump Assembly Figure 39 Oil Pump Assembly 52

60 PARK LOCK GEAR The park lock gear is located on the output shaft. When Park position is selected, the park pawl is engaged with the park lock gear to prevent the transmission output shaft from turning. Remove the components as necessary noting the orientation and position of the components. 1 Park Lock Gear 5 Guide 2 Park Lock Pawl 6 Detent Plate 3 Guide Bushing 7 Spring Assembly 4 Park Lock Connecting Rod 8 Cone Figure 40 Park Lock Gear LTD468 53

61 PLANETARY GEARS IDENTIFICATION AND EVALUATION Pinion, Gears and Carriers The input shaft and K2 input clutch assembly rests inside the K1 clutch and integral front planetary gear set. A thrust bearing isolates the two assemblies. The front planetary annulus gear is the primary input to the transmission and is part of the K2 input clutch assembly. The output shaft is integral with the center planetary pinion carrier and as its name implies, is the output of the transmission. The K3 clutch is located on the output shaft and the remaining center and rear planetary gear set components. The output shaft uses several Teflon seals to isolate lubrication and clutch apply ports. Inspect all seal rings, snap rings, thrust washers and bearings. Inspect the overrunning clutches and associated surfaces for wear grooves or other damage. It is difficult to isolate the three planetary gear sets from the input clutches and holding clutches that drive or lock the gear set components. Some of the gear set components can be both held or driven depending on which clutch is applied. As an example, the center annulus gear and the rear carrier assembly are driven be the K2 clutch, but also held by the B3 clutch when necessary. 54

62 Inspect the gears for noticeable wear, galling, chipped teeth or other damage. Inspect the pinion gears, thrust washers and pins of the carrier assemblies. Check for any loose snap rings associated with the assembly. Obviously damaged gear sets and associated components should be replaced. 1 K1 Clutch 5 Thrust Washer 2 K1 Clutch Hub/Front Sun Gear Shell 3 K3 Clutch, Output Shaft, Center and Rear Planetary Gear Sets 4 Thrust Bearing 6 K2 Clutch, Front Planetary Gear Set and Input Driving Shaft 7 Teflon Sealing Rings Figure 41 Input Clutches and Gear Set Components 55

63 Notes: 56

64 MODULE 3 TRANSMISSION POWERFLOW Figure 42 Clutch Layout GEAR RATIOS AND CLUTCH APPLICATION Table 4 Gear Ratios and Clutch Application GEAR RATIO B1 B2 B3 K1 K2 K3 F1 F A (1) A A (1) H H A A A (1) OR H A A A OR OR A A A OR OR A (1) A A H OR N A A OR OR R 3.16 A (1,3) A A H (3) OR R (2) 1.93 A A A OR OR (1) Clutches required for engine braking during deceleration. (2) When in four-wheel-drive Low (if equipped) or Winter Mode (if equipped). (3) Required for normal reverse ratio. A = Applied, H = Holding, OR = Overrunning 57

65 FIRST GEAR All three planetary gear sets are used to provide the gear reduction for first gear. Clutches B1, K3 and B2 are applied and overrunning clutches F1 and F2 are holding during acceleration. Figure 43 First Gear 58

66 A1 Front Annulus Gear A2 Center Annulus Gear A3 Rear Annulus Gear C1 Front Planetary Carrier C2 Center Planetary Carrier C3 Rear Planetary Carrier S1 Front Sun Gear S2 Center Sun Gear S3 Rear Sun Gear Figure 44 First Gear Schematic First Gear Powerflow Front Gear Set The front annulus gear is driven by the input shaft. The front sun gear is held by the B1 brake. The F1 overrunning clutch holds the front sun gear while accelerating. The front pinions and carrier walk around the held front sun gear. Rear Gear Set The rear annulus gear is driven by the front planetary carrier. The rear sun gear is held by the K3 clutch and the B2 brake. The F2 overrunning clutch holds the rear sun gear during acceleration. The rear pinions and carrier walk around the held rear sun gear. Center Gear Set The center annulus gear is driven by the rear pinion carrier. The center sun gear is held by the B2 brake. The center pinions and carrier walk around the held center sun gear to drive the output shaft. 59

67 D (1st) Acceleration Input shaft drives front annulus gear F1 holds front sun F2 holds center sun gear and rear sun gear together B2 holds center sun gear D (1st) Deceleration (Engine Braking) K3 holds center sun gear and rear sun gear together (both directions) B1 holds front sun gear SECOND GEAR The front gear set provides direct drive while the rear and center gear sets provide the gear reduction. K1, K3 and B2 clutches are applied and F2 overrunning clutch holds during acceleration. Figure 45 Second Gear 60

68 A1 Front Annulus Gear A2 Center Annulus Gear A3 Rear Annulus Gear C1 Front Planetary Carrier C2 Center Planetary Carrier C3 Rear Planetary Carrier S1 Front Sun Gear S2 Center Sun Gear S3 Rear Sun Gear Figure 46 Second Gear Schematic Second Gear Powerflow Front Gear Set The front annulus gear is driven by the input shaft. The front sun gear and front carrier are held together by the K1 clutch, preventing the front pinions from rotating. The front carrier is driven at input shaft speed. Rear Gear Set The rear annulus gear is driven by the front carrier at input shaft speed. The rear sun gear is held by the K3 clutch and B2 brake. The F2 overrunning clutch holds the rear sun gear during acceleration. The rear pinions and carrier walk around the held rear sun gear. Center Gear Set The center annulus gear is driven by the rear pinion carrier. The center sun gear is held by the B2 brake. The center pinions and carrier walk around the held center sun gear to drive the output shaft. 61

69 D (2nd) Acceleration Input shaft drives front annulus gear K1 locks front sun gear and front carrier together for a 1:1 ratio through the front planetary gear set F2 holds the center sun gear and rear sun gear together B2 holds center sun gear D (2nd) Deceleration K3 holds the center sun gear and rear sun gear together (both directions) THIRD GEAR The front and rear gear sets provide direct drive while the center gear set provides the gear reduction. K1, K2 and B2 clutches are applied. Figure 47 Third Gear 62

70 A1 Front Annulus Gear A2 Center Annulus Gear A3 Rear Annulus Gear C1 Front Planetary Carrier C2 Center Planetary Carrier C3 Rear Planetary Carrier S1 Front Sun Gear S2 Center Sun Gear S3 Rear Sun Gear Figure 48 Third Gear Schematic Third Gear Powerflow Front Gear Set The front annulus gear is driven by the input shaft. The front sun gear and front carrier are held together by the K1 clutch, preventing the front pinions from rotating. The front carrier is driven at input shaft speed. Rear Gear Set The rear annulus gear is driven by the front pinion carrier at input shaft speed. The rear carrier is driven by the K2 clutch at input shaft speed, preventing the rear pinions from rotating. The rear carrier is driven at input shaft speed. Center Gear Set The center annulus gear is driven by the rear carrier and K2 clutch at input shaft speed. The center sun gear is held by the B2 brake. The center pinions and carrier walk around the held center sun gear to drive the output shaft. 63

71 D (3rd) Acceleration Input shaft drives the front annulus gear K1 locks the front sun gear and front planetary carrier together for a ratio of 1:1 through the front planetary gear set K2 drives the center annulus gear and the rear planetary carrier B2 holds the center sun gear D (3rd) Deceleration Not applicable, engine braking is provided FOURTH GEAR (DIRECT DRIVE) All three gear sets provide direct drive. K1, K2 and K3 clutches are applied. Figure 49 Fourth Gear 64

72 A1 Front Annulus Gear A2 Center Annulus Gear A3 Rear Annulus Gear C1 Front Planetary Carrier C2 Center Planetary Carrier C3 Rear Planetary Carrier S1 Front Sun Gear S2 Center Sun Gear S3 Rear Sun Gear Figure 50 Fourth Gear Schematic Fourth Gear Powerflow Front Gear Set The front annulus gear is driven by the input shaft. The K1 clutch holds the front sun gear and front carrier together, preventing the front pinions from rotating. The front carrier is driven at input shaft speed. Rear Gear Set The rear annulus gear is driven by the front pinion carrier at input shaft speed. The rear carrier is driven by the K2 clutch at input shaft speed, preventing the rear pinions from rotating. The rear carrier is driven at input shaft speed. Center Gear Set The center annulus gear is driven by the rear carrier and K2 clutch at input shaft speed. The center sun gear is driven by the rear sun gear through the K3 clutch at input shaft speed, preventing the pinions from rotating. The center carrier drives the output shaft. 65

73 D (4th) Acceleration Input shaft drives the front annulus gear K1 locks the front sun gear and front carrier together for a 1:1 ratio through the front planetary gear set K2 drives the center annulus and rear planetary carrier K3 holds the center sun gear and rear sun gear together (both directions) D (4th) Deceleration Not applicable, engine braking is provided FIFTH GEAR (OVERDRIVE) All three planetary gear sets are used to provide fifth gear ratio. B1, K2 and K3 clutches are applied and F1 overrunning clutch holds during acceleration. Figure 51 Fifth Gear 66

74 A1 Front Annulus Gear A2 Center Annulus Gear A3 Rear Annulus Gear C1 Front Planetary Carrier C2 Center Planetary Carrier C3 Rear Planetary Carrier S1 Front Sun Gear S2 Center Sun Gear S3 Rear Sun Gear Figure 52 Fifth Gear Schematic Fifth Gear Powerflow Front Gear Set The front annulus gear is driven by the input shaft. The front sun gear is held by the B1 brake. The F1 overrunning clutch holds the front sun gear during acceleration. The front pinions and carrier walk around the held sun gear at a reduced speed. Rear Gear Set The rear annulus gear is driven by the front pinion carrier at a reduced speed. The rear carrier is driven by the K2 clutch at input shaft speed. The rear pinions walk around the inside of the rear annulus gear. The rear sun gear is driven in overdrive. Center Gear Set The center annulus gear is driven by the K2 clutch at input shaft speed. The center sun gear is driven by the rear sun gear through the K3 clutch, which is being driven in overdrive. The center sun gear drives the center pinions at a reduced speed. The center pinions walk around the inside of the center annulus gear. Even though the center carrier is driven at a reduced speed, the center and rear sun gears are forcing the center carrier and output shaft to rotate faster than the input shaft to provide an overdrive ratio. 67

75 D (5th) Acceleration Input shaft drives the front annulus gear F1 holds front sun gear (one direction) K2 drives center annulus and rear planetary carrier K3 locks the center sun gear and rear sun gear together D (5th) Deceleration B1 holds front sun gear in both directions REVERSE (NORMAL/STANDARD MODE) All three gear sets are used to achieve normal reverse gear ratio. B1, B3 and K3 clutches are applied and F1 overrunning clutch holds during acceleration. Figure 53 Normal Reverse Gear 68

76 A1 Front Annulus Gear A2 Center Annulus Gear A3 Rear Annulus Gear C1 Front Planetary Carrier C2 Center Planetary Carrier C3 Rear Planetary Carrier S1 Front Sun Gear S2 Center Sun Gear S3 Rear Sun Gear Figure 54 Normal Reverse Gear Schematic Normal Reverse Gear Powerflow Front Gear Set The front annulus gear is driven by the input shaft. The front sun gear is held by the B1 brake. The F1 overrunning clutch holds the front sun gear during acceleration. The front pinions and carrier walk around the held front sun gear. Rear Gear Set The rear annulus gear is driven by the front carrier. The rear carrier is held by the B3 brake. The rear pinions drive the rear sun gear in a reverse direction. Center Gear Set The center sun gear is driven by the rear sun gear through the K3 clutch. The center annulus gear is held by the B3 brake. The center pinions walk around the inside of the held annulus gear to drive the center carrier and output shaft in reverse. 69

77 Normal Reverse Acceleration Input shaft drives the front annulus gear F1 holds front sun gear (one direction) K3 locks the center sun gear and rear sun gear together B3 holds the rear planetary carrier/center annulus gear Normal Reverse Deceleration B1 holds front sun gear (both directions) REVERSE 1 (4X4 LOW OR WINTER MODE) The front gear set provides direct drive while the rear and center gear sets provide the reverse gear ratio for 4X4/winter mode. K1, B3 and K3 clutches are applied. Figure 55 Reverse 1 Gear 70

78 A1 Front Annulus Gear A2 Center Annulus Gear A3 Rear Annulus Gear C1 Front Planetary Carrier C2 Center Planetary Carrier C3 Rear Planetary Carrier S1 Front Sun Gear S2 Center Sun Gear S3 Rear Sun Gear Figure 56 Reverse 1 Gear Schematic Reverse 1 Gear Powerflow Front Gear Set The front annulus gear is driven by the input shaft. The front sun gear and front carrier are held together by the K1 clutch, preventing the front pinions from rotating. The front carrier is driven at input shaft speed. Rear Gear Set The rear annulus gear is driven by the front carrier at input shaft speed. The rear carrier is held by the B3 brake. The rear sun gear is driven by the rear pinions in a reverse direction. Center Gear Set The center sun gear is driven by the rear sun gear through the K3 clutch. The center annulus gear is held by the B3 brake. The center pinions walk around the inside of the held center annulus gear to drive the center carrier and output shaft in reverse. 71

79 Reverse 1 Acceleration Input shaft drives front annulus gear B3 holds rear planetary carrier/center annulus gear K3 holds the center sun gear and rear sun gear together K1 locks front sun gear to front carrier (front planetary gear set is 1 to 1) Reverse 1 Deceleration Not applicable NEUTRAL (STANDARD MODE) No power flows to the output shaft. B1 and K3 clutches are applied. A1 Front Annulus Gear C3 Rear Planetary Carrier A2 Center Annulus Gear S1 Front Sun Gear A3 Rear Annulus Gear S2 Center Sun Gear C1 Front Planetary Carrier S3 Rear Sun Gear C2 Center Planetary Carrier Figure 57 Standard Neutral Schematic 72

80 Neutral (Standard Mode) Front Gear Set The front annulus gear is driven by the input shaft. The front sun gear is held by the B1 brake in preparation for first or reverse. The front pinions and carrier walk around the held sun gear. Rear Gear Set The rear annulus gear is driven by the front carrier. The rear carrier is free to rotate. The rear sun gear is also free to rotate. Center Gear Set There is no input member for the center gear set because no power flow has been transmitted from the rear gear set. The K3 clutch is applied to hold the rear and center sun gears together in preparation for first or reverse and are not held to the case by the B2 brake. NEUTRAL (DEFAULT MODE) No power flows through the gear sets. K1 and K3 clutches are applied. A1 Front Annulus Gear C3 Rear Planetary Carrier A2 Center Annulus Gear S1 Front Sun Gear A3 Rear Annulus Gear S2 Center Sun Gear C1 Front Planetary Carrier S3 Rear Sun Gear C2 Center Planetary Carrier Figure 58 Neutral (Default Mode) Schematic 73

81 Neutral (Default Mode) Front Gear Set The front annulus is driven by the input shaft. The K1 clutch is applied to hold the front sun gear and front carrier together. The front carrier is driven at input shaft speed in preparation for default second or normal reverse. Rear Gear Set The rear annulus gear is driven by the front carrier at input shaft speed. The rear carrier is free to rotate. The rear sun gear is also free to rotate. Center Gear Set There is no input member for the center gear set because no power flow has been transmitted from the rear gear set. The K3 clutch is applied to hold the rear and center sun gears together in preparation for default second or standard reverse and are not held to the case by the B2 brake. To achieve 2nd gear in Limp-in Mode, the B2 brake is energized by the position of the manual valve. 74

82 Notes: 75

83 Notes: 76

84 MODULE 4 MAJOR COMPONENT SERVICE OIL PUMP The oil pump can only be serviced by disassembling the transmission. When installing the pump external gear, the chamfer on the gear faces the pump housing. A machining mark on the pump gears is not significant for pump gear timing or orientation. 1 External Gear 5 Oil Pump Housing 2 Internal Gear 6 Crescent 3 Inlet Chamber Gear Chamfer Faces Pump Housing (See Heavy Arrow) 4 Outlet (Pressure) Chamber Figure 59 Oil Pump Assembly Gear Installation 77

85 Measure the dimensions of the gears and housing bore to determine the extent of pump wear and the need for replacement. Inspect for any signs of wear such as pitting, scoring, grooves or any other damage. Table 5 Oil Pump Measurements MEASUREMENT Average Thickness of Gears Average Depth of Gear Bore Average ID of Gear Bore Average OD of External Gear Average OD of Internal Gear DIMENSIONS mm (0.503 in.) mm (0.505 in.) mm (3.427 in.) mm (3.423 in.) mm (2.606 in.) The oil pump has an inner seal (seals torque converter hub) and an outer seal (seals pump housing to torque converter housing). Use seal installer 8902A to properly install the inner hub-to-pump seal. Note the orientation of the outer seal for proper installation. 78

86 Notes: 79

87 VALVE BODY 1 Heat Shield 7 Bolt 2 Valve Body Assembly 8 Drain Plug (If Equipped) 3 Valve Body Retaining Bolt 9 Drain Plug Gasket (If Equipped) 4 Oil Filter Pin Harness Connector 5 Oil Pan 11 Guide Bushing Retaining Bolt 6 Clamping Element 12 Guide Bushing (Extension to Valve Body Connector) Figure 60 Valve Body Assembly 80

88 Solenoid Valve Testing The solenoid valves are located in the upper valve body under the lead frame which provides electrical connection to the 13-pin connector. The solenoid valves are sealed to the valve body using O-rings. A strainer is located under each solenoid valve to protect the valve from contamination. Each solenoid can be checked using a DMM to check the resistance value of the solenoids. To replace a defective solenoid, first remove the solenoid valve protective cap and then remove the bolt and leaf spring securing the solenoid valve to the valve body. 1 Solenoid Valve Cap Shift Solenoid Valve 2 Solenoid Valve Cap 9 TCC Solenoid Valve 3 Bolt (M6X32) /4 5 Shift Solenoid Valve 4 Bolt (M6X30) Shift Solenoid Valve 5 Leaf Spring 12 Lead Frame 6 Modulating Pressure Solenoid Valve 7 Shift Pressure Regulating Solenoid Valve 13 Upper Valve Body (Shift Plate) Figure 61 Solenoid Valve Locations 81

89 To check a solenoid with the transmission installed in the vehicle, disconnect the 13-pin harness connector from the connector extension guide. Locate the appropriate pin numbers for the suspect solenoid valve and measure the resistance of the solenoid windings. Also check for a short to ground. Table 6 Solenoid Valve Resistance Values SOLENOID VALVE OHMS RESISTANCE C (68 73 F) 1 2/4 5 Shift (On/Off) Shift (On/Off) Shift (On/Off) 4.0 TC Clutch (Modulating) 2.5 Shift Pressure Regulating (Variable 5.0 Force) Line Pressure (Variable Force) 5.0 Valve Identification Each valve in the upper and lower valve body halves has a specific purpose and is named for the function the valve performs. For example, the 2 3 shift pressure shift valve activates the 2 3 upshift or the 3 2 downshift. Valve, Check Ball and Strainers The 12 check balls (eight steel and four plastic) used in the NAG 1 transmission are located in the cast pockets in the underside of the valve body just below the separator plate. Check balls need to be inspected very carefully for creases or irregularities. Slight irregularities on a check ball can cause intermittent problems. Remove and install the valve body with the separator plate and transfer plate attached, to prevent the check balls from falling out of the cast pockets in the valve body. It is very important in diagnosis to know which check ball came from which pocket. Use the hydraulic flow diagrams in the service information to determine which gears are affected by a particular leaking check ball. Also, note the positions of any strainers associated with the solenoid valves. The strainers are located in both halves of the valve body. 82

90 INPUT CLUTCHES K1 Input Clutch Evaluate the components as you disassemble the clutch to determine replacement needs. Remove or install the F1 overrunning clutch, paying attention to orientation and direction. Notice the outer disc carrier and piston sealing rings are chamfered. The chamfer faces outward. Remove the selective clutch pack snap ring and multi disc clutch pack. A special multi-use spring compressor (8900) is used to compress the piston spring enough to expose the snap ring for removal. After the K1 clutch has been serviced, clutch pack clearance must be checked. Clutch pack clearance is adjusted by use of a selective snap ring. When checking clearance, a special press tool (8901) is used to apply pressure to the disc pack. The tool is designed to apply the correct amount of pressure by aligning marks on the tool. With the clutch assembled, position the press tool into the clutch. Position the assembly into the shop press and apply pressure until the marks of the tool are aligned. Measure clutch pack clearance using a feeler gauge. Take at least three measurements and average the results. If clearance requires adjustment, obtain the correct selective snap ring, install the snap ring and recheck clearance. 1 Steel Disc (One) 1.8 mm (0.071 in.) 6 Friction Discs (Six) 2 Steel Disc (Five) 2.8 mm (0.110 in.) 7 Clutch Spring 3 Steel Disc (One) 4.0 mm (0.158 in.) 8 Clutch Piston 4 K1 Clutch Hub 5 Selective Snap Ring Figure 62 K1 Input Clutch Stack-Up L Clutch Pack Clearance Measured Between Outer Disc and Selective Snap Ring 83

91 K2 Input Clutch The K2 clutch, when applied, drives the center annulus gear and the rear planet carrier. The outer disc carrier of the K2 clutch is part of and rotates at input shaft speed. As with any clutch assembly, the K2 clutch incorporates friction and steel discs, a piston, piston spring, seals, O-rings and snap rings. Evaluate the components as you disassemble the clutch to determine replacement needs. Notice the inner and outer piston sealing rings are chamfered. The chamfer faces outward. Remove the selective clutch pack snap ring and multi-disc clutch pack. A special multi-use spring compressor (8900) is used to compress the piston spring enough to expose the snap ring for removal. After the K2 clutch has been serviced, clutch pack clearance must be checked. Clutch pack clearance is adjusted by use of a selective snap ring. When checking clearance, a special press tool (8901) is used to apply pressure to the disc pack. The tool is designed to apply the correct amount of pressure by aligning marks on the tool. With the clutch assembled, position the press tool into the clutch. Position the assembly into the shop press and apply pressure until the marks of the tool are aligned. Measure clutch pack clearance using a feeler gauge. Take at least three measurements and average the results. If clearance requires adjustment, obtain the correct selective snap ring, install the snap ring and recheck clearance. 1 Clutch Spring 6 Selective Snap Ring 2 Steel Disc (One) 1.8 mm (0.071 in.) 7 Friction Discs (Six) 3 Steel Disc (Five) 2.8 mm (0.110 in.) 8 Clutch Piston 4 Steel Disc (One) 4.0 mm (0.158 in.) 5 K2 Clutch Outer Disc Carrier Figure 63 K2 Input Clutch Stack-Up L Clutch Pack Clearance Measured Between Outer Disc and Selective Snap Ring 84

92 K3 Input Clutch The K3 clutch, when applied, locks the center sun gear and the rear sun together. As with any clutch assembly, the K3 clutch incorporates friction and steel discs, a piston, piston spring, seals, O-rings and snap rings. Evaluate the components as you disassemble the clutch to determine replacement needs. Notice the piston sealing ring is chamfered. The chamfer faces outward. Remove the selective clutch pack snap ring and multi-disc clutch pack. A special multi-use spring compressor (8900) is used to compress the piston spring enough to expose the snap ring for removal. After the K3 clutch has been serviced, clutch pack clearance must be checked. Clutch pack clearance is adjusted by use of a selective snap ring. When checking clearance, a special press tool (8901) is used to apply pressure to the disc pack. The tool is designed to apply the correct amount of pressure by aligning marks on the tool. With the clutch assembled, position the press tool into the clutch. Position the assembly into the shop press and apply pressure until the marks of the tool are aligned. Measure clutch pack clearance using a feeler gauge. Take at least three measurements and average the results. If clearance requires adjustment, obtain the correct selective snap ring, install the snap ring and recheck clearance. 1 Outer Disc Carrier 6 Clutch Piston 2 Steel Disc (One) 4.0 mm (0.158 in.) 7 Friction Discs (Five) 3 Steel Disc (Five) 2.8 mm (0.110 in.) 8 Selective Snap Ring 4 Steel Disc (One) 1.8 mm (0.071 in.) 5 Disc Spring Figure 64 K3 Input Clutch Stack-Up L Clutch Pack Clearance Measured Between Outer Disc and Selective Snap Ring 85

93 BRAKE (HOLDING) CLUTCHES B2 and B3 Brake Clutches The B2 and B3 brake clutches are removed along with the transmission housing. With the case horizontal, remove the snap ring (selective) retaining the B3 brake clutch components. Remove the B3 clutch discs and reaction plate. Remember to tag the clutch components for reassembly. The B3 piston is also the B2 outer disc carrier. To remove the B2 clutch and components, remove the two retaining bolts located in the rear valve body area of the case. 1 Snap Ring (Selective) 9 B3 Piston Sealing Ring 2 Multiple Disc Pack 10 B2 Piston 3 Disc Spring (Belleville) 11 Piston Guide Sealing Ring 4 B2 and B3 Piston Guide 12 Piston Guide Sealing Ring 5 O-Ring 13 Piston Guide 6 B3 Piston Sealing Ring (Outer) 14 Piston Back Pressure Disc Spring 7 B3 Piston Sealing Ring (Inner) 15 Spring Plate 8 B3 Piston and B2 Outer Disc Carrier 16 Snap Ring Figure 65 B2 and B3 Brake Clutch Components 86

94 After the B2 brake has been serviced, clutch pack clearance must be checked. Clutch pack clearance is adjusted by use of a selective snap ring. When checking clearance, a special press tool (8901) is used to apply pressure to the disc pack. The tool is designed to apply the correct amount of pressure by aligning marks on the tool. With the clutch assembled, position the press tool into the clutch. Position the assembly into the shop press and apply pressure until the marks of the tool are aligned. Measure clutch pack clearance using a feeler gauge. Take at least three measurements and average the results. If clearance requires adjustment, obtain the correct selective snap ring, install the snap ring and recheck clearance. 1 Outer Disc Carrier 6 Steel Disc (Four) 1.8 mm (0.071 in.) 2 Friction Discs (Five) 7 Steel Disc (One) 6.5 mm (0.256 in.) 3 Disc Spring 8 Selective Snap Ring 4 Clutch Piston 5 Steel Disc (One) 1.8 mm (0.071 in.) Figure 66 B2 Brake Clutch Stack-Up L Clutch Pack Clearance Measured Between Outer Disc and Selective Snap Ring The B3 brake clutch is checked and adjusted similar to the input and other brake clutches. However, the B3 brake clutch must be assembled into the transmission housing to be checked and measured. 87

95 B1 Brake Clutch The B1 brake clutch assembly is secured to the torque converter housing from the outside with 11 bolts. The oil pump assembly is retained from the inside through the B1 brake. Remove the oil pump bolts to remove both the oil pump and the B1 brake assembly. With B1 brake assembly removed, the separator plate can be lifted from the torque converter housing. Special tools are used to disassemble the B1 brake. With B1 brake selective snap ring and disc pack and spring removed, a multiple use spring compressor (8900) is used to remove the B1 piston snap ring. Remove the spring and then, blow the piston out using 20 psi air pressure at the port (A) shown. After the B1 clutch has been serviced, clutch pack clearance must be checked. Clutch pack clearance is adjusted by use of a selective snap ring. When checking clearance, a special press tool (8901) is used to apply pressure to the disc pack. The tool is designed to apply the correct amount of pressure by aligning marks on the tool. With the clutch assembled, position the press tool into the clutch. Position the assembly into the shop press and apply pressure until the marks of the tool are aligned. Measure clutch pack clearance using a feeler gauge. Take at least three measurements and average the results. If clearance requires adjustment, obtain the correct selective snap ring, install the snap ring and recheck clearance. 1 Disc Spring 6 Selective Snap Ring 2 Steel Disc (One) 1.8 mm (0.071 in.) 7 Friction Discs (Four) 3 Steel Disc (Three) 2.8 mm (0.110 in.) 8 Clutch Piston 4 Steel Disc (One) 4.0 mm (0.158 in.) 5 Outer Disc Carrier Figure 67 B1 Brake Clutch Stack-Up Opposing Arrows Indicate Clutch Pack Clearance Measured Between Outer Disc and Selective Snap Ring 88

96 OVERRUNNING CLUTCHES The F1 overrunning clutch is installed in the front planetary gear set between the sun gear and the reaction shaft (F1). The F2 overrunning clutch is located between the rear planetary sun gear and center planetary sun gear via the hollow shaft. The overrunning clutches either lock two gear set components together or lock components to the case. When removing these clutches note their orientation and position for reassembly purposes. These clutches can be removed as assemblies. 1 Hollow Shaft 5 Snap Ring 2 Retainer Ring 6 O-Rings (2) 3 F2 Overrunning Clutch 7 Brass End Faces Out (Toward Oil Pump) When Installed 4 K3 Clutch Inner Disc Carrier and Rear Planetary Sun Gear Figure 68 F2 Overrunning Clutch Location 89

97 Notes: 90

98 MODULE 5 TRANSMISSION REASSEMBLY The importance of using all of the appropriate service information cannot be overemphasized. Always follow the repair and assembly procedures for both the individual components of the transmission and the transmission itself. Pay careful attention to the requirements, specifications and adjustments of each component. Do not be in a hurry when disassembling or reassembling the transmission. Accuracy and speed come with familiarity. Attention to all details of each subcomponent and the component s individual parts provides clues to repairing the transmission failure. During assembly, are all thrust washers/bearings, needle bearings and seals correctly installed and fully seated? Make sure to properly tighten fasteners to the recommended torque value. Lubricate all components during assembly and installation. Presoak any new clutch friction discs using the recommended transmission oil. Assembling the transmission methodically, following the service information the first few times, greatly enhances the successful repair of the transmission. REASSEMBLY Install the park lever shaft and all parking assembly components. B2 and B3 Brake Installation Assemble the transmission housing components. Install the park lock gear. Install the B2 brake assembly while orienting the bolt holes to install the retaining bolts. Buildup the B3 brake inside the case. Remember to check and adjust the B3 clutch pack clearance. With the preliminary case components installed, set the assembly aside. Torque Converter Housing, B1 Brake and Oil Pump Place the rubberized intermediate (separator) plate onto the torque converter (bell) housing, making sure to align all bolt holes and fluid passages (do not use any sealant on this plate). Install the B1 clutch assembly to the torque converter housing, aligning the locating dowel pin through the plate and into the housing. Install the B1 brake assembly fasteners and tighten to specification. Flip the torque converter housing and install the oil pump, aligning the bolt holes and fluid passages. Install the oil pump fasteners through the B1 brake and into the pump. Tighten the oil pump bolts to specification. Install a new torque converter hub seal into the oil pump, using seal installer 8902A. K1 Input Clutch Place the torque converter housing on the bench to begin installing the gear train and driving clutches. Support the housing with blocks to provide clearance for the input and reaction shafts. 91

99 Install the K1 clutch assembly (includes front planetary carrier, sun gear and F1 overrunning clutch) over the B1 brake. Make sure that the thrust washer is installed and the K1 input clutch oil passage in the hub is clear. Make sure all B1 brake friction discs are engaged. Make sure the next thrust washer is installed. Input Shaft, Front Annulus and K2 Input Clutch Assembly Make sure the two Teflon seals are installed on the input shaft. Install the input shaft and K2 input clutch assembly over the K1 input clutch assembly. Engage the front annulus gear with the front carrier pinions to the fully seated position. Make sure the thrust bearing is in place. Install the rear annulus gear and snap ring onto the K1 clutch inner hub and front carrier assembly to hold in the input shaft assembly. Output Shaft and Gear Set Assembly, K3 Input and F2 Overrunning Clutches A thrust washer race and thrust bearing must go between the input and output shafts. Install the output shaft assembly. Fully engage the K2 input clutch friction discs with the hub part of the center carrier. Verify that all components are fully engaged and properly seated and that all thrust washers, thrust bearings and needle bearings are positioned correctly and in place. Transmission Housing After all gear train components are installed and fully engaged, place the transmission housing (with park gear, B2/B3 clutches installed) over the gear train and onto the torque converter housing. The housing assembly must be shaken and jiggled into place so that the B2/B3 clutch assemblies can fully engage all clutch discs. Once fully seated on the intermediate plate, install the housing-to-housing bolts and tighten to specification. Check input and output shafts by turning to see if they are free and not binding. Gear Train End Play, Output Shaft Bearing and Seal Using gauge bar 6311 and a depth gauge, calculate the amount of required shim thickness for the correct gear train end play. Calculate the adjustment shim(s) as necessary. Measure from the park lock gear to the gauge bar and from the output shaft bearing surface of the housing to the gauge bar. Install the calculated shim(s). Using bearing installer 9287, install the output shaft bearing. Install the bearing snap ring into the housing and make sure the snap ring is seated correctly. Make sure there is no end play between the output shaft bearing and the snap ring by using a feeler gauge. No play must exist. If there is play, install a thicker snap ring to eliminate the play. Stand the transmission on end and check gear train end play. Use tools , and C Adjust shim(s) as required, or check to make sure all gear train components are fully engaged and seated. 92

100 Install the output shaft seal using seal installer 8902A. Install the output shaft flange and new flange nut. Tighten the nut to specification. Using staking tool 9078 and driver handle C-4171, stack the output shaft flange retaining nut following the service information. Valve Body and Oil Pan Using no more than 30 psi air pressure, check the application of the clutches. Identify the clutch apply ports in the transmission housing using the Student Workbook and service information. Install the valve body assembly and bolts. Tighten the valve body bolts evenly and crosswise to specification. Install a new oil filter, making sure the filter is properly sealed and retained. Install the oil pan, fasteners and hold-down clamps and tighten to specification. Make sure the 13-pin electrical connector guide bushing is installed using new O-rings. Make sure the dipstick tube is installed using a new O-ring and that the dipstick is fully inserted and the cap locked (if applicable). During installation, make sure the torque converter is fully engaged with the input shaft, reaction shaft and inner oil pump gear. 93

101 Notes: 94

102 MODULE 6 HYDRAULIC SYSTEM COMPONENTS SYSTEM PRESSURES The NAG 1 transmission hydraulic system is designed with a number of different levels of pressure regulation. These levels of regulation are required to properly operate the various hydraulic components such as the clutches and the torque converter. The following table provides examples of the various pressure levels. Table 7 System Pressures PRESSURES PRESSURE LEVEL Line Pressure psi Modulating Pressure (P-Mod) psi Shift Pressure Regulating Pressure psi Shift Pressure psi Shift Solenoid Valve Pressure psi Torque Converter Pressure psi TCC Apply Pressure psi Line Pressure The oil pump produces the oil pressure necessary for the transmission hydraulic system to function. Line pressure is the main pressure of the hydraulic system required to supply each clutch with pressure when applied. The line pressure is the maximum pressure in the hydraulic system. All other pressures are derived from line pressure. The level of the line pressure is controlled at the line pressure regulating valve. Line pressure is load dependent by modulating pressure and also gear dependent by K1 clutch or K2 clutch pressure. The minimum (basic) level of line pressure is adjusted by the spring in the line pressure regulating valve. 95

103 Line pressure is regulated within approximately kpa ( psi). Regulation to maximum pressure occurs in first gear and reverse gear. 1 2/4 5 SOL 1 2/4 5 Solenoid Valve SP VFS LU SOL PWM LP VFS SHIFT P REG LP SOL IN PRES (20) Shift Pressure Variable Force Solenoid (VFS) Valve Torque Converter Clutch Solenoid Valve (Pulse Width Modulated) Line Pressure Variable Force Solenoid (VFS) Valve Shift Pressure Regulating Valve VFS Pressure Regulating Valve S. SOL IN P (21) Shift Solenoid Valve Pressure Regulating Valve LP REG (4) SHIFT P REG (19) T/C LIMIT (3) L/U CONT (22) T/C Line Pressure Regulating Valve Shift Pressure Regulating Valve Torque Converter Pressure Limit Valve Torque Converter Clutch/Lubricating Pressure Control Valve Torque Converter Figure 69 Line, Torque Converter, Lubricating, Modulating and Shift Pressures 96

104 Modulating Pressure (P-Mod) Modulating pressure determines the level of line pressure. Modulating pressure also determines the pressure regulated at the three shift overlap valves along with shift pressure. Modulating pressure is adjusted at the modulating pressure solenoid valve (LP VFS). The level of modulating pressure is dependent on engine load. Modulating pressure acts at the line pressure regulating valve and the three shift overlap valves. Modulating pressure is regulated to approximately kpa (0 125 psi). Shift Pressure Shift pressure is the pressure in the clutch as it engages during the shift phase. Shift pressure is regulated by the overlap valve together with the modulating pressure at the clutch as it engages. Shift pressure is what initializes Second gear in Limp-in Mode. The level of shift pressure is determined by the shift pressure solenoid valve (SP VFS) and is regulated to between kpa (0 220 psi). Control Valve Pressure Control valve pressure supplies the regulated line pressure to the modulating pressure control solenoid valve (LP VFS), the shift pressure control solenoid valve (SP VFS) and the shift solenoid valve pressure regulating valve. The control valve pressure is regulated at the regulating valve up to a maximum of 800 kpa (125 psi) depending on the line pressure. 97

105 Shift Solenoid Valve Pressure Shift solenoid valve pressure controls the supply pressure to the three shift solenoid valves. Shift solenoid valve pressure also controls the supply pressure to the TCC solenoid valve which is Pulse Width Modulated (PWM). Shift solenoid valve pressure is derived from the control valve pressure which is regulated at the shift solenoid valve pressure regulating valve. Shift solenoid valve pressure is then supplied to the: 1 2/4 5 shift solenoid valve. 2 3 shift solenoid valve. 3 4 shift solenoid valve. TCC solenoid valve that controls converter clutch pressure. 2 3 shift pressure valve. 3 4 shift pressure valve. The shift solenoid valve pressure is regulated to approximately kpa (50 55 psi). Shift Pressure Regulating Pressure Shift pressure regulating pressure is supplied to the shift pressure regulating valve which determines the working level of shift pressure regulating valve pressure. The level of shift pressure regulating pressure is determined by the shift pressure solenoid valve (SP VFS). The shift pressure regulating pressure is regulated to between kpa (0 120 psi). Torque Converter Clutch (TCC) Regulating Valve The TCC regulating valve controls the TCC apply pressure and provides passage for lubricating oil flow. The valve also provides passage for torque converter return oil to the sump in partial apply mode. In the unapplied mode, the TCC regulating valve provides unrestricted passage for torque converter charge and return oil. The torque converter return oil is then passed through the oil cooler and into the transmission for lubrication. In the applied mode, the TCC regulating valve regulates the TCC modulating pressure. 98

106 Torque Converter Pressure/Lubricating Pressure The torque converter pressure limit valve regulates the pressure in the torque converter. At the line pressure regulating valve, line pressure is supplied to the torque converter pressure limit valve and the regulated pressure is supplied to the torque converter. The return oil from the torque converter is passed through the cooler and into the transmission as lubricating pressure. The torque converter pressure limit valve regulates the oil pressure to a maximum of 690 kpa (100 psi). Figure 70 TCC Regulating Valve and Torque Converter Pressure Limit Valves 300C and Grand Cherokee vehicles are equipped with an oil cooler bypass valve that is located in line between the transmission and the oil cooler. The oil cooler bypass is thermostatically controlled to maintain a minimum transmission temperature by recirculating oil into the transmission, bypassing the external oil cooler. Transmission adaptation does not occur when the transmission oil temperature is below 140 F (60 C). 99