RECEIVER 0860967 - Caterpillar

Illustration 1 g00922465General Description
The power train consists of four basic systems. The following systems are the four basic systems:
Power Train/Chassis Electronic Control Module
Torque Converter and Updrive Gears
Transmission and Output Transfer Gears
Differential and Final DrivesThe four basic systems are connected by an electrical connection, a hydraulic connection, a magnetic connection, or a mechanical connection.The operation of the power train begins at the Power Train/Chassis Electronic Control Module (Power Train/Chassis ECM). The Power Train/Chassis ECM receives the information of the selected operating speed from the shift lever switch in the electrical system. The Power Train/Chassis ECM uses the information from the switches and the sensors in the electrical system to control the hydraulic system of the torque converter and transmission. This is done by energizing the appropriate solenoids.The torque converter has a lockup clutch for direct drive and a one-way clutch for torque converter drive. In torque converter drive, the torque converter drives the transmission hydraulically. The torque converter is fastened directly to the flywheel of the engine.The lockup clutch solenoid is activated by the Power Train/Chassis ECM when direct drive is required. When the lockup clutch solenoid is activated, the lockup clutch is hydraulically engaged. The rotating housing of the torque converter is mechanically connected to the output shaft of the torque converter. The drive shaft mechanically connects the torque converter to the torque converter updrive gears. The torque converter updrive gears are fastened directly to the torque converter. The upper drive shaft mechanically connects the torque converter updrive gears to the transmission.The upshift solenoid and the downshift solenoid hydraulically activate the rotary actuator of the transmission. Movement of the rotary actuator mechanically selects the position of the rotary selector spool. The flow through the rotary selector spool hydraulically activates the correct valves in the pressure control valve. These valves engage the correct transmission clutches. This mechanically connects the transmission input shaft to the output shaft, through the output transfer gears to the differential. The transmission will not drive the output shaft unless there is power flow through the torque converter. The power flow can be hydraulic or mechanical.After the transmission and the torque converter are connected, power is supplied from the engine to the differential through the torque converter, the torque converter updrive gears, the transmission, and output transfer gears. The axles mechanically connect the differential to the final drives. When the transmission is in the correct speed position, the mechanical movement of the rotary selector spool causes the transmission gear switch to electrically signal the Power Train/Chassis ECM that the shift is complete. With the rotation of the transmission output shaft, the transmission output speed sensors electrically transmits the output speed of the transmission to the Power Train/Chassis ECM.Brief Summary of Operation
The shift lever switch selects the desired speed and direction.
The transmission output speed sensors magnetically measure the transmission output speed.
The Power Train/Chassis ECM determines the proper moment for shifting by using the signals from the transmission output speed sensors, the shift lever switch, and the transmission gear