GM 4L80-E transmission

4L80-E/4L85-E
Overview
Manufacturer	General Motors
Production	1991–
Body and chassis
Class	4-speed longitudinal automatic transmission
Chronology
Predecessor	Turbo-Hydramatic
Successor	6L80/6L90

The 4L80-E (and similar 4L85-E) was a series of automatic transmissions from General Motors. Designed for longitudinal engine configurations, the series included 4 forward gears. It was an evolution of the Turbo-Hydramatic 400, first produced in October, 1963. 4L80-Es were optioned only in Chevrolet/GMC pickups, vans, and commercial vehicles, and the Hummer H1. It was also adopted by Rolls Royce in 1991 and modified, after extensive testing, and used initially in the Bentley Continental R, and subsequently other Rolls Royce and Bentley vehicles.

The 4L80 and 4L85 were built at Willow Run Transmission in Ypsilanti, Michigan.

Gear ratios:

The "MT1" 4L80-E is able to handle engines with up to 440 ft·lbf (597 N·m) of torque. Final drive ratios include 3.42, 3.73, and 4.10.

The 4L80E was rated to max GVWR of 18,000 (Axle and vehicle dependent) Applications:

The "MN8" 4L85-E is able to handle vehicles with up to 460 ft·lbf (624 N·m) of torque. Final drive ratios include 3.42, 3.73, and 4.10.

The 4L85E is able to handle vehicles with a GVWR of up to 18,000 lbs (dependent on axle ratio and vehicle)

Applications:

Note: These transmissions have issues with early style 12 pin harnesses in which transmission fluid leaks around the harness and shorts the pinouts causing transmission to go into "limp mode" This issue can be easily rectified by simply cleaning the plug.

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