I have 2002 chevy Marlo Carlo ss with 3800 in it and was wanting to know if a transmission from 01 Grand Prix with a 3800 super changed would work in my Marlo Carlo

 

The question is - why do you want to do the swap?

It will work, but there are a couple important differences:
-the sprocket ratios are different. The HD trans has a lower ratio (similar to putting a numerically lower rear end in a rwd car). As such, the pcm tune should be modified to account for this.
-the differential is different, and you will need a different passenger axle to accommodate
-the torque converter diameters are different (ie the HD converter won't bolt up to a non HD flexplate, they need to be matched)

If the intent is to do this for better strength, I wouldnt bother. You can upgrade the main part that's heavier duty (the diff) on your existing trans if you really want to.

 

So this ^^^^ is something Ive wanted to ask for a while..

What about going the other way around.. Putting the weaker trans on an L67?

Sorry to threadjack but seems similar enough..

 

I struggle with the term 'weaker trans'. The HD and non HD share most of the same parts. The only notable strength difference is the diff. Even then, the vast majority of diffs I've seen fail are from burnouts with greatly different wheel speeds (1 wheel burnout in the most extreme case). They don't seem to typically fail from launching too hard.

I don't see a regular trans failing notably earlier than an HD trans on a supercharged application, especially with just bolt ons.

For any kind of decently modded 3800, if I was pulling the trans, id definitely be putting a built one back in though.

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