DESCRIPTION & OPERATION
The Hydra-Matic 4T65-E transaxle uses 2 electric solenoids to control transaxle upshifts and downshifts. Each solenoid is turned on or off by the Powertrain Control Module (PCM). PCM function includes on-board self-diagnostics. The on-board self-diagnostics feature helps identify which components or circuits may need further testing.
Each solenoid either holds hydraulic pressure (solenoid on) or releases hydraulic pressure (solenoid off). This action controls shift valves inside control valve body. By switching one or both solenoids on or off, different combinations of clutches, sprags and bands are operated. See SHIFT SOLENOID OPERATION .