System Description

Electronic Four-Speed Automatic Transmission:

The Hydra-matic 4L80-E electronic four-speed automatic transmission incorporates electronic controls that utilize the transmission control module (TCM) to control shift points, torque converter clutch apply and release, and line pressure. Inputs from sensors and switches provide engine, transmission and vehicle operating information to the TCM. The TCM uses this information to determine the precise moment to upshift or downshift, apply or release the torque converter clutch, and what line pressure is required to apply the clutches or bands. This type of control, based on the operating conditions of the vehicle, results in consistent and precise shift points and shift quality.

NORMAL and SPORT modes:
Two operating strategies are available to the driver:

NORMAL: Normal mode provides economy operation by causing the transmission to upshift at lower engine speeds and throttle openings. Start-off occurs in second gear unless the accelerator is depressed to the kick down position. High-speed performance is available as required.


SPORT: Sport mode allows the engine power to be used to its full potential at all times. Start-off occurs in first gear and upshifts and kick down are tailored to performance.