Description & Operation: Introduction

WARNING: This page is about a different car, the 2002 Buick Regal, 2002 Buick Century, 2001 Buick Regal, and 2001 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

The 4T65-E is a fully automatic front wheel drive electronically controlled transaxle. The 4T65-E provides four forward ranges including overdrive. The Powertrain Control Module (PCM) controls shift points by means of two shift solenoids. A vane-type oil pump supplies the oil pressure. The PCM regulates oil pressure by means of a pressure control solenoid valve.

All vehicles equipped with a 4T65-E transaxle have an Electronically Controlled Capacity Clutch (ECCC) system. In the ECCC system, the pressure plate does not fully lock to the torque converter cover. Instead it is, precisely controlled to maintain a small amount of slippage between the engine and the turbine, reducing driveline torsional disturbances.

You can operate the transaxle in any one of the following seven modes:

P - Park position prevents the vehicle from rolling either forward or backward. For safety reasons, use the parking brake in addition to the Park position.
R - Reverse allows the vehicle to be operated in a rearward direction.
N - Neutral allows the engine to be started and operated while driving the vehicle. If necessary, you may select this position to restart the engine with the vehicle moving.
D - Overdrive is used for all normal driving conditions. Overdrive provides four gear ratios plus a converter clutch operation. Depress the accelerator to downshift for safe passing.
3 - Drive position is used for city traffic and hilly terrain. Drive provides three gear ranges and drive range prevents the transaxle from operating in 4th gear. Depress the accelerator to downshift.
2 - Manual 2nd provides two gear ratios under most operating conditions. Manual 2nd provides acceleration and engine braking. Select this range at any vehicle speed, but the transaxle will not downshift into 2nd gear until the vehicle speed drops below approximately 62 MPH.
1 - Manual Low provides maximum engine braking. You may also select this range at any vehicle speed, but the transaxle will not downshift into 1st gear until the vehicle speed drops below approximately 37 MPH.