Page 13 of 27 Transmission Hydraulic System In Forward (Engine Running - Type 2 & 3 Control Valve Shown) (4) Transmission control valve. (5) Neutralizer valve. (6) Neutralizer solenoid. (7) Flow control spool. (8) Forward/reverse
Page 14 of 27 selector valve. (9) Oil filter. (10) Load piston. (11) Oil pump. (12) Relief valve. (13) Check valve for load piston. (14) Orifice for load piston. (15) Inlet relief valve for torque converter. (16) Screen. (17) Oil cooler. (18) Oil reservoir. (19) Torque converter. (20) Orifice for torque converter bypass. (21) Orfice. (22) Supply passage to 4-WD clutches. (23) Orfice. (24) Relief valve (4-WD only). (25) Transmission lubrication system. (A) Pressure tap for reverse clutch. (B) Pressure tap for pump. (C) Pressure tap for forward clutch. (D) Pressure tap for torque converter inlet. (E) Pressure tap for torque converter outlet. (F) Pressure tap for lubrication and cooling. (G) Pump oil. (H) Return oil. (J) Converter inlet oil. (K) Supply oil. (L) Converter outlet oil. (M) Lubrication oil. The basic components of the hydraulic system for operation of the transmission and torque converter are: oil reservoir (18), oil screen (16), oil pump (11), oil filter (9), torque converter (19), flow control spool (7), relief valve (12), load piston (10) for shift modulation, check valve (13) for load piston, forward/reverse selector valve (8), neutralizer valve (5), neutralizer solenoid (6), relief valve (15) for converter inlet, oil cooler (17), forward clutch pack (1) and reverse clutch pack (2). All oil passages are inside the transmission case and transmission control valve (4) body, except the two transmission hydraulic lines connected to oil cooler (17). From serial number 3DJ1-UP, 5PC4451-UP, 7BC1163-UP, 6TC1364-UP and 5KF1-UP, an external tube provides an oil passage from the relief valve passage to the neutralizer valve passage. Torque Converter, Transmission Pump, Screen And Filter The oil for the operation, cooling and lubrication of the transmission and torque converter is made available by an internal gear pump. The pump is located at the transmission input shaft. The torque converter stator support and pump are assembled together and the assembly is bolted to the transmission case. The pump is driven by the torque converter impeller housing. The oil reservoir for the transmission and torque converter is in the bottom of the transmission case. Oil from the reservoir flows through the pipe assembly to the screen and through the transmission case passages to the suction side of the positive displacement pump. The oil from the pump flows to the filter and then the transmission hydraulic controls. If there is a restriction in the oil filter or if the viscosity of the oil is very high, the bypass valve in the filter housing will open. If the inlet pressure to the oil filter is 117 to 131 kpa (17 to 19 psi) greater than the outlet pressure, the bypass valve will open. When the oil does not go through the filter element, unfiltered oil could cause damage to other components in the hydraulic system. Correct maintenance must be used to make sure that the element does not become plugged and stop the flow of clean oil to the hydraulic system. The filter is mounted to the left side of the transmission case. The screen is mounted inside the transmission case. The screen can be removed on the right side of case. Location Of Oil Filter
Page 15 of 27 Location Of Screen (Behind Plug Assembly) Power Train Oil Cooler The power train oil cooler is mounted in the bottom tank of the radiator. System oil with high temperature comes from the torque converter outlet. This oil goes in one side of the core assembly. The flow of oil is through the core assembly, as coolant flows around the core assembly. In this way, heat is removed from the oil and is given to the coolant. After the oil flows through the cores, it goes out through the outlet passage at the other end of the core assembly and has a lower temperature. The cooler oil then goes to the transmission lubrication and cooling. Location Of Power Train Oil Cooler
Page 16 of 27 Transmission Lubrication System Transmission Lubrication The only pressure lubrication in the transmission is for the forward and reverse shuttles, discs, plates and bearings. After the oil has been cooled by the oil cooler, the oil will enter the right side of the transmission case and go to the right end of the input shaft. Oil flows down the oil passages in the shaft and cools and lubricates the bearings, plates and discs. The other gears and bearings are splash lubricated. The movement of the gears in the oil reservoir causes oil to be thrown on all components. Hydraulic Controls NOTE: Serial number breaks for the different types of control valves are: Type 1; 5PC1-5PC4450, 7BC1-7BC1162, and 6TC1-6TC1363. Type 2; 3DJ1-3DJ173, 5PC4451-5PC8078, 7BC1163-7BC2628, 6TC1364-6TC4297 and 5KF1-5KF466. Type 3; 3DJ157-UP, 5PC8079-UP, 7BC2629-UP, 6TC4297-UP and 5KF467-UP. Location Of Transmission Hydraulic Controls
Page 17 of 27 The torque converter inlet oil pressure is limited by relief valve (15) mounted in the valve adapter. The valve adapter is mounted between the control valve and the transmission case. The relief valve limits the pressure to the torque converter to 750 kpa (110 psi) The transmission hydraulic controls are installed on top of the transmission case. Inlet oil to operate the hydraulic controls comes from oil filter (9). Flow control spool (7) provides a predetermined maximum flow rate to the transmission circuit and bypasses excess flow to the torque converter circuit. The orifice down the center of the spool provides the oil for the transmission circuit. The flow control spool position will change to maintain needed flow through the control valve as load changes. Location Of Neutral/Start Switch Forward/reverse selector valve (8) rotates to direct pressurized oil to the forward or reverse clutch pistons or to drain if in NEUTRAL. The selector valve also allows the clutch pistons to drain if they are not engaged. The selector valve also activates and deactivates the neutral/start switch. If the selector valve is left in a forward or reverse position when the vehicle is turned off, the selector valve will deactivate the neutral/start switch so the vehicle cannot be started until the selector valve is returned to the neutral position at next start-up. The forward/reverse selector valve is mechanically actuated by a mechanical linkage and the direction control lever mounted on the steering wheel column. Location Of Direction Control Lever Neutralizer valve (5) and neutralizer solenoid (6) are used when the transmission is to have a speed change or full horsepower is required at the loader hydraulics. Location Of Neutralizer Button On Shift Lever
Page 18 of 27 Location Of Neutralizer Button On Loader Lever The neutralizer solenoid is controlled by two neutralizer button switches. One switch is located on the gear shift lever and the other on the loader lever. To activate the neutralizer solenoid, the neutralizer button switch would be pushed in and held until the shift is complete or the loader function is complete. The button is released to deactivate the neutralizer solenoid. When the neutralizer solenoid is activated a rod extends to the left, moving neutralizer valve (5) to the left too. As the neutralizer valve moves to the left a drain port is opened, allowing most pressurized oil for the transmission circuit to go to the drain (reservoir). The oil pressure in the directional clutch circuit decreases and the directional clutch disengages. When the neutralizer solenoid is deactivated the rod retracts and the spring returns the neutralizer valve, closing the drain port, refilling the directional clutches and allowing the transmission to gain pressure again. Do not operate the engine at high idle speed with cold transmission oil. The cold oil may prevent the neutralizer valve from functioning properly and the machine could move. The modulating relief valve consists of relief valve (12) and load piston (10). The modulating relief valve provides a variable relief valve, controls the rate pressure rises in the forward or reverse clutch pack and limits maximum clutch pressure. Orifice (14), in the cover for load piston (10), controls the rate the load piston engages. Check valve (13) allows the load piston to dump oil rapidly.
Page 19 of 27 Transmission Hydraulic System In Neutral (Engine Running - Type 1) (1) Forward clutch assembly. (2) Reverse clutch assembly. (3) Input shaft assembly. (4) Transmission control valve. (5) Neutralizer valve. (6) Neutralizer solenoid. (7) Flow control spool. (8) Forward/reverse selector valve. (9) Oil filter. (10) Load piston. (11) Oil pump. (12) Relief valve. (13) Check valve for load piston. (14) Orifice for load piston. (15) Inlet relief valve for torque converter. (16) Screen. (17) Oil cooler. (18) Oil reservoir. (19) Torque converter. (20) Orifice for torque converter bypass. (A) Pressure tap for reverse clutch. (B) Pressure tap for pump. (C) Pressure tap for forward clutch. (D) Pressure tap for torque converter inlet. (E) Pressure tap for torque converter outlet. (F) Pressure tap for lubrication and cooling. Operation
Page 20 of 27 Starting The Engine (Transmission in Neutral) Transmission Hydraulic Control Valve (Type 2) (4) Transmission control valve. (5) Neutralizer valve. (6) Neutralizer valve. (7) Flow control spool. (8) Forward/reverse selector valve. (10) Load piston. (12) Relief valve. (13) Check valve for load piston. (14) Orifice for load piston. (23) Orfice. (A) Pressure tap for reverse clutch. (C) Pressure tap for forward clutch. (D) Pressure tap for torque converter inlet. (G) Pump oil. (H) Return oil. (J) Converter inlet oil. When the engine is started oil pump (11) pulls oil from reservoir (18) through screen (16) to the pump. The pump sends the oil through filter (9) to control valve (4). Orifice (23) allows oil pump to bleed air to tank during initial start up. Orifice (23) also provide additional oil flow to the torque converter with out passing through flow control valve (7). Oil pressure moves flow control spool (7) to the right. This allows oil not needed by the transmission circuit to flow to the torque converter circuit. On the machines with type 1 control valves, oil needed by the transmission circuit flows through the orifice in the center of flow control (7) spool and goes to forward/reverse selector valve (8). On the type 2 control valve machines, oil needed by the transmission circuit, flows through the orifice in the center of flow control spool (7) and goes to the neutralizer valve (5), through the external tube. Then, the oil goes to the forward/reverse selector valve (8). In NEUTRAL, the selector valve directs oil flow to the reservoir (drain), thus neither forward or reverse clutch pack can be pressurized. The clutch oil passages are open to drain. Since neutralizer solenoid (6) has not been activated, nothing occurs at neutralizer valve (5).
Page 21 of 27 With the forward/reverse selector valve in neutral there is low residual pressure within the control valve. So little pressure is sent to load piston (10) for modulation. Relief valve (12) pressure may be as low as initial relief setting. Transmission Hydraulic Control Valve (Type 3) (4) Transmission control valve. (5) Neutralizer valve. (6) Neutralizer valve. (7) Flow control spool. (8) Forward/reverse selector valve. (10) Load piston. (12) Relief valve. (13) Check valve for load piston. (14) Orifice for load piston. (23) Orfice. (A) Pressure tap for reverse clutch. (C) Pressure tap for forward clutch. (D) Pressure tap for torque converter inlet. (G) Pump oil. (H) Return oil. (J) Converter inlet oil. On the type 3 control valve machines, oil needed by the transmission circuit, flows through the orifice in the center of flow control spool (7) and goes to the neutralizer valve (5), through the external tube. Then, the oil goes to the forward/reverse selector valve (8). In NEUTRAL, the selector valve blocks oil flow, thus neither forward or reverse clutch pack can be pressurized. The clutch oil passages are open to drain. Since neutralizer solenoid (6) has not been activated, nothing occurs at neutralizer valve (5). With the forward/reverse selector valve in neutral there is full oil pressure built up within the control valve. So pressure is sent to load piston (10) for modulation. Relief valve (12) maintains full relief pressure.
Page 22 of 27 Transmission Hydraulic System In Forward (Engine Running - Type 1) (1) Forward clutch assembly. (2) Reverse clutch assembly. (3) Input shaft assembly. (4) Transmission control valve. (5) Neutralizer valve. (6) Neutralizer solenoid. (7) Flow control spool. (8) Forward/reverse selector valve. (9) Oil filter. (10) Load piston. (11) Oil pump. (12) Relief valve. (13) Check valve for load piston. (14) Orifice for load piston. (15) Inlet relief valve for torque converter. (16) Screen. (17) Oil cooler. (18) Oil reservoir. (19) Torque converter. (20) Orifice for torque converter bypass. (A) Pressure tap for reverse clutch. (B) Pressure tap for pump. (C) Pressure tap for forward clutch. (D) Pressure tap for torque converter inlet. (E) Pressure tap for torque converter outlet. (F) Pressure tap for lubrication and cooling.
Page 23 of 27 Engine Running (Neutral To Forward) Transmission Hydraulic Control Valve (Type 2 And Type 3) (4) Transmission control valve. (5) Neutralizer valve. (6) Neutralizer valve. (7) Flow control spool. (8) Forward/reverse selector valve. (10) Load piston. (12) Relief valve. (13) Check valve for load piston. (14) Orifice for load piston. (A) Pressure tap for reverse clutch. (C) Pressure tap for forward clutch. (D) Pressure tap for torque converter inlet. (G) Pump oil. (H) Return oil. (J) Converter inlet oil. When the direction control lever on the steering wheel column is moved to the forward position (away from the driver), the linkage moves forward/reverse selector valve (8) to the forward position. With the engine running, oil pump (11) pulls oil from reservoir (18), through screen (16), to the pump. The pump sends the oil through filter (9) to the control valve. Oil pressure moves flow control spool (7) to the right. This allows oil not needed by the transmission circuit to flow to the torque converter circuit. Oil needed by the transmission circuit flows through the orifice in the center of the flow control spool and goes to forward/reverse selector (8). With the selector valve in the forward position, oil is directed to forward clutch assembly (1). The reverse clutch oil passage is open to drain. Oil fills the forward clutch and then modulation occurs. Orifice (21) maintains oil pressure to 4-WD clutches when oil pressure drops during transmission directional clutch shifts.
Page 24 of 27 The function of modulating relief (12) valve and load piston (10) is to control the rate of the pressure increase in the directional clutch circuit and limit the final clutch pressure as follows for smooth engagement of the clutch. As the pressure in the transmission circuit increases, relief valve (12) starts to move to the right and load piston (10) starts to move to the left. Orifice (14), in the supply passage to the load piston, causes the oil to go to the area behind the load piston at a specific rate. As the relief valve moves to the right and the load piston to the left, the pressure in the forward clutch assembly increases gradually. This gradual increase in pressure is known as modulation. When the load piston reaches its full stroke the relief valve will relieve excess flow to the reservoir and maximum system pressure is reached. Since neutralizer solenoid (6) has not been activated nothing occurs to change the clutch engagement. Engine Running (Forward To Reverse) When the direction control lever on the steering wheel column is moved from the forward position to the reverse position, the linkage moves forward/reverse selector valve (8) from the forward to the reverse position. Orifice (21) maintains oil pressure to 4-WD clutches when oil pressure drops during transmission directional clutch shifts. As the selector valve changes position it passes through the neutral setting. At this position the system pressure is open to reservoir, causing modulating relief valve (12) and load piston (10) to return to a neutral position. The spring behind the load piston forces the oil to drain by opening check valve (13). As oil drains, load piston (10) moves all the way to the right. Once the selector valve is in the reverse position, oil pressure is directed to reverse clutch assembly (2). The forward clutch is open to drain. Modulation operates similar in REVERSE as it does in FORWARD. See NEUTRAL to FORWARD for explanation.
Page 25 of 27 Transmission Hydraulic System In Forward With Neutralizer Activated (Engine Running - Type 1) (1) Forward clutch assembly. (2) Reverse clutch assembly. (3) Input shaft assembly. (4) Transmission control valve. (5) Neutralizer valve. (6) Neutralizer solenoid. (7) Flow control spool. (8) Forward/reverse selector valve. (9) Oil filter. (10) Load piston. (11) Oil pump. (12) Relief valve. (13) Check valve for load piston. (14) Orifice for load piston. (15) Inlet relief valve for torque converter. (16) Screen. (17) Oil cooler. (18) Oil reservoir. (19) Torque converter. (20) Orifice for torque converter bypass. (A) Pressure tap for reverse clutch. (B) Pressure tap for pump. (C) Pressure tap for forward clutch. (D) Pressure tap for torque converter inlet. (E) Pressure tap for torque converter outlet. (F) Pressure tap for lubrication and cooling.
Page 26 of 27 Engine Running (Forward With Neutralizer Activated) Transmission Hydraulic Control Valve (Type 2 And Type 3) (4) Transmission control valve. (5) Neutralizer valve. (6) Neutralizer valve. (7) Flow control spool. (8) Forward/reverse selector valve. (10) Load piston. (12) Relief valve. (13) Check valve for load piston. (14) Orifice for load piston. (A) Pressure tap for reverse clutch. (C) Pressure tap for forward clutch. (D) Pressure tap for torque converter inlet. (G) Pump oil. (H) Return oil. (J) Converter inlet oil. To activate neutralizer solenoid (6) the neutralizer button switch located on either the shift lever or loader control lever must be pushed in and held. When the neutralizer solenoid is energized the solenoid will move neutralizer valve (5) to the left. This shuts off supply oil and opens a drain passage for forward clutch oil and a drain passage for system pressure to proceed to the reservoir. The forward clutch instantly loses pressure thus putting the transmission in NEUTRAL. Load piston (10) and relief valve (12) return to their NEUTRAL position. Load piston check valve (13) allows oil to the right of the load piston to go to drain quickly. At this time relief valve (12) has a lower (initial setting) relief pressure for the transmission circuit. Orifice (21) maintains oil pressure to 4-WD clutches when oil pressure drops during neutralization for transmission speed shifts. The transmission will remain in NEUTRAL until the neutralizer button switch is deactivated (released). When the neutralizer button is released, the neutralizer solenoid is de-energized. With the solenoid deenergized the neutralizer valve spring will return the neutralizer valve to the right, thus closing off both drain passages. Oil pressure is then allowed to fill the directional clutch and increase to maximum system pressure thus returning the transmission to the direction that was selected.
Page 27 of 27 Do not operate the engine at high idle speed with cold transmission oil. The cold oil may prevent the neutralizer valve from functioning properly and the machine could move.