PISTON AS 2959518 - Caterpillar

Illustration 1 g00498556
Basic diagram for the power train systemsThe power train is made up of four basic systems. The following systems are the four systems:
Power Train Electronic Control Module
Torque Converter
Transfer Gears and Transmission
Differential and Final DrivesThe four basic systems have a hydraulic connection, an electrical connection, a magnetic connection, or a mechanical connection.Power is supplied from the engine to the torque converter. Power goes from the torque converter to the transfer gears. The power then goes to the transmission. If the transmission is in gear power flows from the transmission to the differential. The rear axles mechanically connect the differential to the final drives. The final drives are connected to the rear wheels. Power is then sent to the tires.The operation of the power train begins at the Power Train Electronic Control Module (Power Train ECM). The Power Train ECM receives information of the selected speed of operation through the shift lever switch in the electrical system. The Power Train ECM uses the information from several switches and sensors in the electrical system to control the torque converter and the transmission hydraulic system. This is done by energizing the appropriate solenoids.The rotating housing of the torque converter is fastened directly to the engine flywheel. The torque converter has a lockup clutch for direct drive and a one-way clutch for torque converter drive. During torque converter drive, the torque converter drives the transmission hydraulically. During direct drive, there is a direct connection between the engine flywheel and the transmission.The Power Train ECM will activate the lockup clutch solenoid when direct drive is necessary. When the lockup clutch solenoid is activated, the lockup clutch is hydraulically engaged. The lockup clutch becomes a direct connection between the rotating housing and the output shaft of the torque converter. The full power from the engine flywheel is transmitted through the torque converter when the torque converter is in direct drive.The output shaft of the torque converter is connected to a drive shaft. The drive shaft mechanically connects the torque converter to the transfer gears. The transfer gears are fastened directly to the transmission.The Power Train ECM will activate the upshift solenoid or the downshift solenoid when shifts are needed. 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. The transmission clutches mechanically connect the transmission input shaft to the output shaft and to the differential.When the rotary selector spool is in the position to engage the correct transmission clutches, the transmission gear switch will electronically signal the Power Train ECM that the shift is complete. The Power Train ECM will stop energizing the upshift solenoid or the downshift solenoid.When the output shaft of the transmission is rotating, the transmission speed sensor electrically signals the Power Train ECM that the machine