The 4T65E was a transmission manufactured by General Motors from 1998-2011. It replaced the 4T60E starting in the mid to late nineties. It is designed for transverse mounted engines (front/all wheel drive). That’s what the “T” in it’s name stands for, as opposed to the 4L65E, which is for longitudinal (rear wheel drive) vehicles.
It was an incredibly versatile transmission and could have up to twelve different final drive ratios. This allowed it to go in vehicles as different as the Chevy Uplander to the Oldsmobile Intrigue.
When going to find one in the salvage yard, it pays to make sure that you have one from the vehicle that you are looking to put it in. There are so many combinations of torque converter and electrical connections that it creates many compatibility issues.
These transmissions use many different sized torqe converters depending on which application they went originally went in. The easiest way to determine which of the transmissions that you have is to use the RPO codes.
RPO codes can be found on a sticker inside the glove compartment of all modern GM vehicles. Just open it up and look until you see one of these codes. Below you’ll find a list of the codes. this will tell you what version of the transmission you’re looking at.
M15– The M15 was the most common versions of this transmission. It appeared in a heck of a lot of different cars. 245mm torque converter.
M76– This version of the 4T65E has the same converter size as the M15, but has the ability to service all four wheels. 245mm torque converter.
MN3– The MN3 was not very common. It only appeared in the Buick Regal, Park Avenue, and the Oldsmobile Intrigue. 258mm torque converter.
MN7– The MN7 is the high performance version of this transmission commonly known as the 4t65E-HD transmission. It is highly desirable. More on it directly below. 258 mm torque converter.
The 4T65E-HD transmission is the high performance version of the standard 4T65E. It was capable of going behind the LS4 V8, which put down 300+ horsepower at the rear wheels. This makes it far and away the most desirable of the 65E family.
Here are the vehicles that it was found in:
- 2006-2007 Chevrolet Monte Carlos SS
- 2006-2009 Chevrolet Impala SS
- 2005-2008 Pontiac Grand Prix GXP
- 2008-2009 Buick LaCrosse Super
As you can see, this version of the transmission was not available for a long time. If you are looking for one in the salvage yards, check the glove box for the RPO code MN7. You may be better off paying to have your transmission rebuilt by a professional than finding one of these in the wild.