GM 4L80E, 4L85E Automatic Transmission

4L80E & 4L85E Transmission Ratios & Specs

The 4L80E is an evolution of the heavy duty TH400. Whereas the TH400 had only 3 forward speeds, the 4L80 features an overdrive 4th gear. The need for an overdrive transmission is essentially the reason for retiring the TH400. The 4L80 and TH400 have identical ratios, with the exception of the 4L80's 0.75:1 overdrive. It was used for 3/4 and 1 ton pickups with either the 6.2L or 6.5L diesel.

The 4L85E, a variation with a slightly higher input torque capacity, was used behind the Duramax diesel in GMC/Chevrolet vans until the 2005 model year, when the 6 speed 6L90 replaced it. Half ton 6.2L/6.5L diesels of the same period received the lighter duty 4L60 instead of the 4L80. The transmission is electronically controlled, and was used in GM gasoline applications until 2009. The transmission was trumped by the Allison 1000 when the Duramax diesel was introduced for the 2001 model year and would have never held up to the engine's rated torque.

 

4L80E & 4L85E Ratios

1st

2nd

3rd

4th

R

2.482 : 1

1.482 : 1

1.00 : 1

0.750 : 1

2.077 : 1

 

4L80E & 4L85E Transmission Specs

Transmission:

General Motors 4L80E & 4L85E

Type:

4 speed automatic overdrive transmission

Predecessor:

TH400

Model Years/Applications:

1991 - 2005, 6.2L/6.5L (4L80E) and 6.6L Duramax Diesel (4L85E, vans only)

Case Material:

Die cast aluminum

Max Input Torque:

4L80E

440 lb-ft (597 N-m) engine torque

4L85E

460 lb-ft (624 N-m) engine torque

Max GVWR:

18,000 lbs

Max GCWR:

22,000 lbs

Weight:

236 lbs dry, 260 lbs w/ fluid

ATF Type/Spec:

DEXRON VI automatic transmission fluid, ~ 13.5 qts total capacity (may vary by application)

Additional Info:

RPO code "MT1"

4

Four speed transmission

L

Longitudinally mounted

80

High torque capacity, 885 lb-ft maximum gearbox torque

E

Electronically controlled