Description & Operation: Introduction

The 4L30-E automatic transmission is electronically controlled, providing 4 forward speeds and Reverse. Transmission uses a gear-type oil pump to supply all hydraulic pressure needed for operation. Transmission consists of a torque converter, 4 clutch assemblies, planetary gears and brake band. See Figure.

Transmission shifting and torque converter lock-up are controlled by Powertrain Control Module (PCM) or Transmission Control Module (TCM), depending on model application. The control module receives information from various input devices and uses this information to control shift solenoids, band apply solenoid and Torque Converter Clutch (TCC) solenoid. Control module uses input signals to control force motor solenoid (also referred to as pressure control solenoid) operation, which activates pressure regulator valve for controlling line pressure.

A torque management control system is used to reduce engagement shock caused by a change in vehicle speed during shifting. Control module contains a self-diagnostic system which stores a Diagnostic Trouble Code (DTC) if a specified failure or problem is present in transmission electronic control system. If a DTC has set, transmission light (CHECK TRANS) or Sport Mode Light (STL) on instrument cluster will illuminate. DTC may be retrieved to determine transmission problem area. For additional information on self-diagnostic system, see HYDRA-MATIC 4L30-E ELECTRONIC CONTROLS article.

Transmission is capable of 3 different shift modes. These modes are ECONOMY/NORMAL mode, SPORT/POWER mode and WINTER mode. ECONOMY/NORMAL and SPORT/POWER mode may be selected by pressing SPORT/POWER mode switch. SPORT/POWER mode indicator light will illuminate. WINTER mode may be selected by pressing button mounted on center console, near gearshift lever. Shift modes are used to change transmission shift points for various vehicle operating conditions. See OPERATING MODES .

Transmission is equipped with shift lock system. Shift lock system prevents gearshift lever from being moved from Park unless brake pedal is depressed, ignition is on and release button on gearshift lever is depressed.