The 4L80-E (and similar 4L85-E) is a series of automatic transmissions from General Motors. Designed for longitudinal engine configurations, the series included 4 forward gears. It was the 4-speed electronically commanded evolution of the 3-speed 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,[1] 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.
The 4L80-E (RPO MT1) is rated to handle engines with up to 440 ft·lbf (597 N·m) of torque.[2] The 4L80-E is rated to a maximum GVWR of 18,000 lb, depending on the axle and vehicle.[3]
The 4L80-E uses two shift solenoids, initially called Shift Solenoid A and Shift Solenoid B; they were later changed to comply with OBD-II regulations to 1-2 shift solenoid and 2-3 shift solenoid. By activating and deactivating the solenoids in a predetermined pattern by the PCM, four distinct gear ratios can be achieved. The shift solenoid pattern, also sometimes referred to as solenoid firing order, is as follows:
The 4L85-E (RPO MN8) is rated to handle vehicles with up to 690 ft·lbf (935 N·m) of torque.[4] The 4L85E is rated to handle vehicles with a GVWR of up to 18,000 lbs (dependent on axle ratio and vehicle)[5]
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