DESCRIPTION
The 4L80-E transmission uses 2 electric shift solenoids to control transmission upshifts and downshifts. In addition, a force motor (also referred to as pressure control solenoid) controls hydraulic line pressure, and a Torque Converter Clutch (TCC) solenoid controls TCC application. Solenoid is turned on and off by the Powertrain Control Module (PCM) or Transmission Control Module (TCM). PCM/TCM has on-board self-diagnostics to help identify any components or circuits that may need further testing.
OPERATION
Shift solenoid holds hydraulic pressure when it is on and releases pressure when it is off. This action controls the 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 APPLICATION CHART table under ELECTRONIC TESTING.