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| Illustration 1 | g00481737 |
Components of the power train hydraulic system (1) Oil sampling valve (2) Final drive (3) Steering clutch and brake module (4) Breather vent (5) Torque converter outlet relief valve (6) Flywheel housing (7) Power train oil cooler (8) 3116 engine (9) Torque converter scavenge screen (10) Torque converter (11) Pump section (torque converter scavenge screen) (12) Pump section (controls section) (13) Pump section (torque converter and lubrication section) (14) Power train oil pump (15) Filter bypass valve (16) Power train oil filter (17) Filter element (18) Priority valve (19) Steering clutch and brake valve (20) Torque converter inlet relief valve (21) Screen and magnet (22) Bevel gear case (main sump) (23) Transmission (24) Lube for bevel gear (25) Transmission lube (26) Revolutions (RPM) (27) Temperature probe (28) Pressure tap (kPa) (B1) Left side brake pressure (B2) Right side brake pressure (C1) Left side clutch pressure (C2) Right side clutch pressure (L1) Transmission lube pressure (LB1) Left hand clutch/brake lube pressure (LB2) Right hand clutch/brake lube pressure (M) Torque converter inlet pressure (N) Torque converter relief valve (pressure) (PV) Priority valve pressure (Q1) Power train oil temperature (AA) Rear view of the transmission | |
Power Train Oil System
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| Illustration 2 | g00309283 |
Power train oil pump (A) Torque converter and lubrication section (B) Control section for the transmission clutches, steering clutches, and brakes (C) Torque converter scavenge section | |
The power train oil system has a three-section gear pump. The pump is mounted on the rear of the torque converter housing. The pump is driven by gears inside the torque converter. The bevel gear case is the main sump for the power train oil system. The following control sections take in oil from the bevel gear case: (A) torque converter and lubrication section, (B) controls section and (C) torque converter scavenge section. This oil passes through a screen and a magnet.
The oil from section (A) and section (B) is sent separately to the priority valve. From the priority valve, the oil is sent in two directions. Part of the oil flows through a tube in the bevel gear case in order to lubricate the transmission. The rest of the oil goes to the torque converter. The oil from the torque converter flows through the outlet relief valve which maintains a minimum oil pressure inside the torque converter. From the outlet relief valve, the oil flows through a hose to the power train oil cooler. From the cooler, the oil lubricates the steering clutch and brake modules.
The priority valve makes oil from section (A) available for steering, braking, and transmission control. The oil flow from section (B) is used for torque converter operation, lubrication of the steering clutches and brakes, and lubrication of the transmission.
The controls section (B) of the power train oil pump takes oil from the bevel gear case. The oil is sent through a passage in the priority valve to the power train oil filter. From the filter, the oil goes back to the priority valve and flows through tubes in the bevel gear case. Then, the oil flows to the following controls: steering, brake valve and transmission controls. This oil controls the steering clutches and brakes and the transmission clutches. The priority valve makes sure that oil is first available for brake operation. Then, the oil is available for transmission operation.
Transmission control (B) includes the selector and pressure control valve which controls the pressure and flow of the oil to the transmission clutches for engagement. The lube relief valve inside the selector and pressure control valve controls the maximum pressure of the transmission lubrication oil.
Torque converter scavenge pump section (C) removes oil from the torque converter housing. This oil is returned to the bevel gear case.