DESCRIPTION
The 4T80-E transaxle uses 2 electric solenoids to control transaxle upshifts and downshifts. Transaxles also use a transaxle pressure control solenoid (force motor) solenoid to control line pressure, Transaxle Fluid Temperature (TFT) sensor, pressure switch assembly, 2 speed sensors: Vehicle Speed Sensor (VSS) and Transaxle Input Sensor (TIS), and a lock-up control solenoid for Torque Converter Clutch (TCC) operation. Each solenoid is turned on or off by the Powertrain Control Module (PCM). PCM also includes on-board self-diagnostics. This helps identify which parts or circuits may need further testing.
OPERATION
Each solenoid either holds hydraulic pressure (solenoid on) or releases hydraulic pressure (solenoid off). This action controls shift valves inside valve body. By switching one or both solenoids on or off, different combinations of clutches, sprags and bands are operated. See CLUTCH & BAND APPLICATIONS under TROUBLE SHOOTING.