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| Illustration 1 | g00357372 |
Power train hydraulic system schematic (1) Priority valve (2) Wire harness for the electronic control module (3) Torque converter inlet relief valve (4) Power train oil filter (5) Modulating valves and the main relief valve (transmission) (6) Steering and brake control valve (7) Steering clutches and brake (8) Passage for the lubrication of the transmission and the bevel gear (9) Oil cooler (10) Torque converter outlet relief valve (11) Torque converter (12) Power train oil pump (13) Pump drive (14) Passage to the steering clutch and brake lubrication (15) Check valve | |
The power train hydraulic system uses three-section pump (12) for the oil flow:
Section (A) - Transmission and controls section
Section (B) - Torque converter and lubrication section
Section (C) - Transmission and torque converter scavenge section
Power train oil pump (12) is mounted on the front of the bevel gear case. The pump is driven by an auxiliary drive shaft from the engine. The bevel gear case is the sump for the power train hydraulic system.
Transmission and Controls Section
Section (A)
Section (A) of pump (12) draws oil from the bevel gear case through a screen and a magnet. The oil is sent to oil filter (4) . The oil then flows to both steering and brake control valve (6) and transmission controls (5) . A main relief valve is located in a manifold on the top of the transmission planetary group. This relief valve controls the pressure in the system.
The oil that flows past the main relief valve provides part of the lubrication and the cooling for the transmission and the bevel gear case. Oil from section (A) of pump (12) is primarily used to control steering clutches and brakes (7) and the transmission clutches.
Torque Converter and Lubrication Section
Section (B)
Section (B) of pump (12) sends oil from the bevel gear case to priority valve (1) . Priority valve (1) sends a portion of the oil to torque converter (11) . The rest of the oil is sent as lubrication for the steering clutches and brakes and the transmission.
The oil for operation of torque converter (11) exits through outlet relief valve (10) . The oil then flows to oil cooler (9) . The cooled oil is sent back to priority valve (1) . The oil is combined with the oil that bypassed torque converter (11) .
The oil that is combined at priority valve (1) flows to the transmission and the steering clutches and brakes. This oil serves as lubrication for the transmission and the steering clutches and brakes before returning to the bevel gear case. A small portion of the flow is diverted from the torque converter inlet in order to lubricate the gears of pump drive (13) and the bearings.
Priority valve (1) normally sends oil from section (B) of pump (12) to torque converter (11) and steering clutches and brakes (7) . A portion of this oil is also sent to the transmission for lubrication.
When priority valve (1) is alerted by the electronic control module, the oil is diverted from section (B) of pump (12) . The oil is sent through check valve (15) . The check valve is mounted on the pump. This oil is combined with the oil from section (A) of the pump. These flows are combined until a minimum oil pressure is maintained for controlling steering clutches and brakes (7) and the transmission.
Torque converter inlet relief valve (3) is located in priority valve (1) . The inlet relief valve limits the maximum oil pressure to torque converter (11) .
Transmission and Torque Converter Scavenge Section
Section (C)
Section (C) of pump (12) removes oil from the torque converter housing and the transmission case. The oil is returned to the bevel gear case. This oil is drawn through screens at torque converter (11) and the transmission.