The Specifications of a 4L65E Transmission

by John Wasinski

The General Motors Hydramatic 4L65-E automatic transmission is based on the ubiquitous 4L60-E, but is beefed up with heavy duty components for greater strength and performance.


The 4L65-E was developed for use in GM trucks, but has been adapted for use in the Chevrolet Corvette, in GM Australia's Holden Monaro and in other performance cars. The 2005-2006 Pontiac GTO was adapted from the Holden Monaro and uses the 4L65-E transmission.

It is utilized in the Cadillac Escalade AWD and other trucks using GM's 6.0-liter eight-cylinder gasoline engine. These include the Chevrolet Silverado, Chevrolet SSR, GMC Sierra, GMC Sierra Denali, GMC Yukon XL Denali, Hummer H2 and Hummer H3.

It is also available for aftermarket purchase.

Power Ratings

According to Super Chevy, the truck version rates at 380 pound-feet of torque and nearly 400 pound-feet of torque in the car version. Steve Ford, a chief GM engineer, states that the 4L65-E "can handle about 20 percent more torque than the 'L60.'"

The maximum engine torque for the 4L65-E is 380 pound-feet and the maximum gearbox torque with the 4L65-E is 670 pound-feet. Maximum shift speeds are 6,400 rpm from first to second gear, 6,200 rpm from second to third gear and 5,600 rpm from third to fourth gear.


The 4L65-E transmission's model number refers to its basic features: it is a four-speed transmission, is positioned longitudinally and is electronically controlled.

In newer vehicles, according to Novak Conversions, it may be referred to as the 4L65, since all General Motors units have electronic control and there are no non-electronically controlled 4L65-type transmissions.

It is also known as the M32 transmission option. The M30 designation refers to the older 4L60-E transmission.


The 4L65-E has five-pinion planetary carriers. It has large sun-shell gears that are manufactured from powdered metal, which is a process that increases the strength of the components. The bell housing fully encloses the torque converter, which reduces vibration.

According to Super Chevy, the 4L65-E also features heat-treated stator shaft splines and an induction-hardened turbine shaft.

Other 4L60-E parts have been replaced with heavier-duty components.

Its wet weight, according to Ultimate GTO, is 194.6 pounds.

Gear ratios are 3.059-to-1 for first gear, 1.625-to-1 for second gear, 1-to-1 for third gear and 0.0696-to-1 for fourth gear.


The Hydramatic 4L65-E is manufactured in the United States at Toledo Transmission in Toledo, Ohio and at Romulus Transmission in Romulus, Mich.

Romulus Transmission also produces the 4L65-E in Ramos Arizpe, Mexico.

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