TERMINAL 1748704 - Caterpillar

When the engine is started, the transmission oil pump (8) pulls oil from oil sump (19) . The oil flows through the suction screen and magnet (18) . Transmission oil pump (8) sends pressurized oil through transmission oil filter (1) . Pressurized transmission oil flows from the transmission oil filter to the oil inlet in the torque converter priority valve (4) . The pressurized oil to the priority valve (4) also flows to the modulating valve for the impeller clutches and lockup clutches. The pressurized oil is directed in two different directions after the oil exits torque converter priority valve (4) . The pressurized oil flows to relief valve (2) . The pressurized oil also flows to clutch solenoid modulating valves (11-16) . Number 3 modulating valve (15) is energized because the transmission is in neutral. None of the remaining clutch solenoid modulating valves (11) , (12) , (13) , (14) and (16) provide oil to the transmission clutches. The pressurized oil leakage drains to oil sump (19) .Torque converter inlet relief valve (3) routes the inlet oil to torque converter (6) . Torque converter outlet oil flows through torque converter outlet relief valve (5) to oil cooler (10) . Oil from torque converter inlet relief valve (3) also combines with oil from oil cooler (10) . After the oil cools, the oil flows to the transmission for transmission lubrication (17) . After the transmission is lubricated and cooled the oil drains to the transmission oil sump (19) .Torque converter inlet relief valve (3) limits torque converter inlet oil pressure to a maximum of 1060 100 kPa (154 15 psi). Torque converter inlet relief valve (3) is located inside transmission hydraulic control relief valve (2) . Shifting the Transmission from the NEUTRAL position to the FIRST SPEED FORWARD position
Illustration 3 g01242766
Hydraulic System Schematic (1) Transmission Oil Filter (2) Transmission hydraulic control relief valve (3) Torque converter inlet relief valve (4) Torque converter priority valve (5) Torque converter outlet relief valve (6) Torque converter (7) Modulating valve for the lockup clutch (8) Transmission oil pump (9) Modulating valve for the impeller clutch (10) Transmission oil cooler (11) Modulating valve for number 1 clutch (12) Modulating valve for number 4 clutch (13) Modulating valve for number 2 clutch (14) Modulating valve for number 5 clutch (15) Modulating valve for number 3 clutch (16) Modulating valve for number 6 clutch (17) Lubrication of the transmission planetary (18) Suction screen and magnet (19) Oil sump (20) Lubrication of the input transfer gears (A) Torque converter inlet pressure tap (B) Pressure tap for pump pressure (C) Pressure tap for the modulating valve (lockup clutch) (D) Torque converter outlet pressure tap (E) Pressure tap for the modulating valve (impeller clutch) (AA) Pressure oil (BB) Torque converter outlet pressure (CC) Torque converter clutch oil (DD) Torque converter inlet oil (EE) Return oilThe power train electronic control module (ECM) modulates the electrical current that is sent to the selected clutch solenoid modulating valves.