Will a 4T65E non HD trans work with a SC engine?

**Charlie** · 10-27-2009

I recently bought a 1998 Pontiac Grand Prix GTP wich i got a pretty good deal on it cause of the problem its having,
The transmission won't shift into 4th gear and the guy who sold me the car told me he had already changed both shift solenoids and that didn't fix the problem so i'm just thinking on changing the whole transmission but had no luck finding a 4T65E HD so i thinking about going for a non HD,
Does anyone done this before and did you have any problems?
and will the non HD trans be able to handle a the power of the SC engine?

Thanks in advance

**nicksilvergt99** · 10-27-2009

Well i forget which, zzperformance or 3800 performance, but they sell an HD upgrade for non HD transmissions for less than a hundred bucks.

**Charlie** · 10-27-2009

Since i still have the HD transmission could i use the diff and other parts to convert a non HD to an HD?

**Charlie** · 10-27-2009

One more thing would i be able to use any 4T65E transmission cause there's like four different ones(M15,M67,MN3 and MN7) do all of these have same gear ratios?

**BillBoost37** · 10-28-2009

The reason you don't have 4th gear is most likely the 4th gear hub shaft has stripped. This is common.

You can use a non-hd transmission if you have the gearing reprogrammed in your pcm. You can also use your HD parts in the new transmission. As long as you stay 98+ you should be good swapping parts. In 97 the diff/output shafter were slightly different.

If you used a non-hd trans with the HD diff, you'd have a 3.29 gear ratio.

**JDCMoney** · 10-28-2009

Read this post..

http://www.grandprixforums.net/f21/m...ons-22602.html

Trannyman answers it pretty well

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