PLATE 1772494 - Caterpillar

Illustration 1 g00643773
(1) Torque converter scavenge pump section (2) Torque converter charging pump section (3) Parking brake release pump section (4) Cover for the torque converter scavenge screenThe pump has three sections:
torque converter scavenge pump section (1)
torque converter charging pump section (2)
parking brake release pump section (3) The pump is driven by a gear on the torque converter.The torque converter scavenge section (1) is located on the drive end. This pump takes oil from the bottom of the torque converter housing. The oil flows through a scavenge screen that is behind cover (4). The oil is then returned to the hydraulic tank.The other two sections get oil from the hydraulic tank.The torque converter charging section (2) sends the oil to the torque converter charging oil filter, to the torque converter inlet relief valve, and to the torque converter.The parking brake release section (3) sends oil to the parking brake release oil filter. This oil is then divided. The parking and secondary brake valve receives some of the oil. This oil is used to release the spring applied parking brakes. The rest of the oil that was divided flows to the lockup clutch and to the pulled unit control valve. This oil is used to engage the lockup clutch in the torque converter. The oil that was sent to the pulled unit control valve is used as signal oil.