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 front wheel drive fully automatic transmissions from General Motors. Designed for transverse engine configurations, the series includes 4 gear bearing overdrive ^[1][2] 2 electronic shift solenoids, and electronic force motor to control line pressure. ^[3]

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 to ECCC.^[1][4][2][3]

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

4T80-E

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. ^[1]

The 4T80-E is a hydramatic transmission and was developed for use with V8 front-wheel-drive cars, and at the time exclusively the Cadillac Northstar engine^[5]. 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.^[6]

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^[7] (may not be true) . 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).^[8]

Gear ratios:

Applications: ^[9][8]

• 3.11:1
  • 1994–2005 Cadillac Deville
  • 1993-2002 Cadillac Eldorado
  • 1993-2004 Cadillac Seville
  • 2006 Cadillac DTS
• 3.48:1
  • 1995-1999 Oldsmobile Aurora
• 3.71:1
  • 1996–2005 Cadillac Deville Concours/DTS
  • 1993-2002 Cadillac Eldorado ETC
  • 1993-2004 Cadillac Seville STS
  • 1995-1999 Oldsmobile Aurora
  • 2004–2005 Pontiac Bonneville GXP
  • 2006-2011 Buick Lucerne V8
  • 2001-2003 Oldsmobile Aurora V8

Issues

the transmission had no performance parts, causing stress at over 300 hp^[4]

and in some use cenarios, faulty seals will degrade the entire transmission^[10]

most of these where fixed in the later models ^[11]