GM 4T80 transmission

4T80-E
A Hydra-Matic 4T80 transmission at the Ypsilanti Automotive Heritage Museum
Overview
Manufacturer	General Motors
Production	1993–2011
Body and chassis
Class	4-speed transverse automatic transmission
Chronology
Predecessor	Turbo-Hydramatic 125
Successor	6T70

The 4T80E is a series of automatic transmissions from General Motors. Designed for transverse engine configurations, the series includes 4 forward gears. The 4Txx family is an evolution of the original Turbo-Hydramatic 125 transverse automatic introduced in the 1980 model year "X" body.

The 4T80-E transmission is electronically controlled and features an automatic overdrive transaxle with an electronically controlled torque converter clutch. The 4T80 originally used a viscous clutch, but this was changed in 2005.

The 4T80 is built at Willow Run Transmission in Ypsilanti, Michigan.

The "MH1" 4T80-E is able to handle vehicles up to 8000 lb (3628.74 kg) GVWR. The final drive ratio is 3.11:1, 3.48:1, or 3.71:1. The 4T80 uses a viscous torque converter clutch, which was replaced with EC3 (electronically controlled converter clutch) in 2004.

The 4T80-E is a hydramatic transmission and was developed for use with V8 front-wheel-drive cars, specifically for the Cadillac Northstar engine. It was designed with extreme power handling capabilities at the time. The 4T80-E debuted in the Cadillac Allante in 1993 along with the Northstar Double Overhead Camshaft (DOHC) V8. It reportedly cost 80% more than a similar GM 4T60 transmission and weighed 60 lb (27 kg) more.

This transaxle has been used in many of GM's front drive large sedans. The Cadillac Division had exclusive usage of the 4T80-E until the 1995 Oldsmobile Aurora debuted. The Aurora had the 4.0L version of the Northstar V8 coupled to a 4T80-E. It wasn't until 2004 that Pontiac got usage of this transaxle in the Bonneville GXP which employed a 275 horsepower version of the Northstar 4.6L V8.