Hey everybody I have another Question about the difference between a 4t65e (M15) and a 4t65e-HD (MN7). I have an (M15) and want to upgrade it to an HD version. I know that the major difference between these two transmissions is the differential. However, I want to replace the differential in my tranny with an HD diff from zzp. I am curious, does anyone know if gm used different clutches and steels in the two trannys? if they did ill just rebuild the whole thing while i have it out. Any help would be greatly appericated thanks

To the best of my knowledge the innards of a 4T65E and 4T65E-HD are the same. IE: solenoids, valve body, bands, servos, clutches, splines, sprag, etc.

The major difference is the beefier differential and the passenger side drive axle.

Since ZZP has the 4T65E HD tranny upgrade for a lot less than replacing the transmission that seems the best route to go.

BTW - What year and model is your Grand Prix?

To the best of my knowledge the innards of a 4T65E and 4T65E-HD are the same. IE: solenoids, valve body, bands, servos, clutches, splines, sprag, etc.

The major difference is the beefier differential and the passenger side drive axle.

Since ZZP has the 4T65E HD tranny upgrade for a lot less than replacing the transmission that seems the best route to go.

BTW - What year and model is your Grand Prix?


CORRECT! :smokin:

thanks guys i appericate the info

The best part is that you dont have to pull the tranny to replace the Diff or pass side drive axle. These trannys have a cover (cant remember which side, think its the drivers') that with a few bolts, and the CV shaft removed we can change the diff w/ the trany and motor in the car

Diff is on the passenger side