Description & Operation: Introduction

The 4L80-E is a fully automatic rear wheel drive electronically controlled transmission. The 4L80-E provides four forward ranges including overdrive and reverse. A gear type oil pump controls shift points. The Powertrain Control Module (PCM) and the Pressure Control (PC) solenoid regulate these shift points. The PCM also controls shift schedules and Torque Converter Clutch (TCC) apply rates. Transmission temperature also influences shift schedules and TCC apply rates.

You can operate the transmission in any one of the following 7 modes:

• P - Park position prevents the vehicle from rolling either forward or backward on vehicles less than 15,000 GVW. 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.
• OD - 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.
• D - Drive position is used for city traffic, and hilly terrain. Drive provides three gear ranges. Depress the accelerator to downshift.
• 2 - Manual 2nd provides acceleration and engine braking or greater traction from a stop. When you choose manual 2nd, the vehicle will start out in 1st gear and upshift to 2nd gear. You may select this gear at a vehicle speed of up to 35 MPH.
• 1 - Manual low provides maximum engine braking. You may select this gear at a vehicle speed of up to 20 MPH.