Overhaul - 4T80-E: Description

The Hydra-Matic 4T80-E transaxles are fully automatic 4-speed units consisting primarily of a 3-element hydraulic torque converter and converter clutch. Some models use a viscous converter clutch and other models use a torque converter clutch for converter lock-up.

Transaxle uses 3 gear-type pumps to supply all hydraulic pressure needed for operation. A scavenge pump removes oil from the lower oil pan. This oil is pumped into the side oil pan. A primary oil pump takes oil from the side oil pan and supplies line pressure oil. A secondary oil pump takes oil from the side oil pan and supplies remaining oil for initial clutch apply, forced downshifts, wide open throttle and reverse gear operations.

The multiplied torque from torque converter is transferred to the transaxle by a sprocket and drive link assembly. Other internal components consist of 4 multiple disc clutches, a roller clutch, 2 sprag clutches, 2 bands and 2 planetary gear sets. The final drive gear and differential assemblies are bolted on end of transaxle.

The 4T80-E uses 2 electronic shift valves controlled by the Powertrain Control Module (PCM). Transaxles also use a transaxle pressure control solenoid (force motor) solenoid to control line pressure, transaxle temperature sensor, pressure switch assembly, 2 speed sensors (Vehicle Speed Sensor - VSS and Transaxle Input Sensor - TIS), and a lock-up control solenoid for Torque/Viscous Converter Clutch (TCC or VCC) operation.