Thread: 03 tranny, convert to HD or not?

what year is the car

the car it will be going in is a 03. maybe I should reword this... I'm doing a top swap on a 03 GP GT, I have a full parts 99 GTP. I was going to put the HD tranny from the GTP in the 03, but I read someone that the 03 trannys are stronger? So should I take the diff of the donor tranny and put it on the 03 tranny?

The trans info you need to know:
An 03 is different than the rest the valve body and channel plate are not the same, not compatible.
There are a few threads (search on me) about putting an 03 into an non 03 car by swapping some pins.
You can definately put the HD diff into your 03 trans, ensure you can program the gear ratio change, if there is a change. The end result would be 3.29 gearing. (I say if because the beer is starting to keep me from remembering what your 03 ratio is stock)
The passenger axle would need to be swapped over as well. The HD diff is longer and therefore the axle is shorter than the non-hd.
There are a few updates that GM made for the 03 year. Problem there is.. what was your car's production date? I've seen 10/02 and 11/02 prod dates on cars and the 4th clutch shaft was not hardened at that point. So an 03 car might not have all the upgraded parts. If the trans is out, it's worth a set of channel plate gaskets to find out.

Hope that info helps out.

Always trust your RPO codes.

Here's the build info: Hold on they're chopped.

There we go. I always wanted to get this info and post it. Someone probably already did though.