Electra Park Avenue V6-231 3.8L VIN C SFI (1989)
Torque Converter: Description and Operation
Fig. 2 Turbo Hydra-Matic 440-T4 Automatic Transaxle
The 440-T4 and 440-T4E transaxles are fully automatic units which provides four forward speeds including an overdrive top gear. The transmission
unit includes a three element hydraulic torque converter and lock-up clutching element, four multiple disc clutch, two bands and a compound reaction
planetary gear set, Fig. 2. Power transmitted to the drive wheels from the planetary gear through a final drive gear set and differential assembly.
The converter is designed to provide torque multiplication during acceleration and at slow vehicle speed, and lock-up during normal operation for
increase operating economy. Operation of the converter lock-up is controlled automatically by the engine fuel system electronic control module. In
addition, the converter drives the vane type oil pump by means of a shaft splined to the converter cover.
The torque converter hydraulically couples the engine to the planetary gears through a turbine and shaft assembly which drives the transmission output
shaft by means of a drive link chain and sprockets.