HUB-FAN PULLEY 4P3878 - Caterpillar

The hydraulic system for the power train supplies oil to the torque converter and the planetary transmission.Transmission Hydraulic System
Illustration 1 g02571256
(1) Oil filter bypass valve (2) Modulating valve (Torque converter lockup clutch) (3) Transmission hydraulic control relief valve (4) Transmission oil temperature sensor (5) Modulating valves (Electronic clutch pressure control) (6) Torque converter inlet relief valve (7) Transmission oil filter (8) Torque converter lockup clutch (9) Torque converter (10) Oil cooler (11) Transmission oil pump (12) Transmission lubrication (13) Transmission oil temperature sensor (14) Scavenge screen (15) Sump (16) Torque converter outlet relief valve (17) Lube flow diverter valve (18) Torque converter flow valve
Illustration 2 g02571316
(1) Oil filter bypass valve (2) Modulating valve (Torque converter lockup clutch) (3) Transmission hydraulic control relief valve (4) Transmission oil temperature sensor (5) Modulating valves (Electronic clutch pressure control) (6) Torque converter inlet relief valve (7) Transmission oil filter (8) Torque converter lockup clutch (9) Torque converter (10) Oil cooler (11) Transmission oil pump (12) Transmission lubrication (13) Transmission oil temperature sensor (14) Scavenge screen (15) Sump (16) Torque converter outlet relief valve (17) Lube flow diverter valve (18) Torque converter flow valveThe transmission is controlled, cooled, and lubricated by oil that is supplied from sump (15) of the planetary transmission by transmission oil pump (11) .Oil is taken from the sump of the planetary transmission by the transmission oil pump. Oil is fed via transmission oil filter (7) to the following components:
Modulating Valve (Torque Converter Lockup Clutch)
Modulating Valves (Electronic Clutch Pressure Control)
Transmission Hydraulic Control Relief ValveTest points for oil pressure and an oil temperature sensor are incorporated in the hydraulic system.Control of the planetary transmission is achieved by electronically activated modulating valves (5) that allow oil to fill the various clutches in the planetary transmission.Torque converter (9) allows the power to be transmitted smoothly from the engine to the planetary transmission. The torque converter allows the speeds of the engine and the transmission to be matched smoothly. Once the speeds are matched, modulating valve (2) for torque converter lockup clutch (8) engages torque converter lockup clutch (8) in torque converter (9). The torque converter provides drive from the engine to the planetary transmission.Oil is fed to the torque converter and the oil transmits the drive from the engine to the planetary transmission. Outlet oil from the torque converter goes via torque converter outlet relief valve (16) to the oil cooler and forward as lubricant for transmission (12) .