4-speed 4T80 automatic

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 2005. Transmission broadcast codes in 2005 for the ECCC transmission are 5ABN and 5MMN. 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 Allanté 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. The 4T80-E was last used in 2011 on the Cadillac DTS and the Buick Lucerne (when equipped with the 4.6L Northstar).