Convert 4t65e to HD

**timboku** · 03-28-2010

Looking at replacing my trans while I have my engine replaced. I am having trouble finding a cheap low mile HD trans. If I got a non HD trans, is it a matter of swapping to the HD diff out of my current trans and then tuning for the gears?
Is there a right up on how to do this? Any thoughts would be great. Thanks.

**OH4CompG** · 03-28-2010

That's about it. Now some people will say you will need the HD trans output shaft, I personally threw an HD diff in with an HD diff cover with my stock output shaft when I owned my impala and it ran just fine.

**Scimmia** · 03-29-2010

If you've got the output shaft, use it. It's longer than the non-HD unit, so using that one may not seat fully.

**Lawngoose** · 03-29-2010

X2^ thats what I did.

**timboku** · 03-29-2010

Thanks, I am replacing the engine with an L26 Top swap from a 2008 car and I will use the trans from a 2002 Venture van, (Junkyard says its the same trans and it only has 40k on it/ I am researching a little more to make sure).
Do I need to swap out flex plates and toruqe converters or will the flex plate on the L26 be fine with the torque converter from the 4t65e... will it just all bolt right up? Also, anything I should do to the trans while it is out of the car to beef it up or help it out???

**Scimmia** · 03-29-2010

There are two different size converters, 245mm and 258mm. Which one is on your engine and which is on your transmission will depend on what cars they were in. Some of the later flexplates were even drilled for both.