raxxus

Hey guys.

I recently picked up a 99 Trans Am. I'm pulling a few things off it and putting them on my 95 before I sell the 95. The 99 has the GU6 2.73 gears (auto). I'm going to be ordering a manual trans from Hawks, but would like better gears. The 95 has 3.42. Is it worth swapping the rears? I know I'll need to do something with the axles as the brakes aren't a direct swap. Anything else that might cause an issue? Or should I just order gears and have a local shop install them?

Thanks!

Injuneer

Minor point, but 2.73's are GU2 and 3.42's are GU6.

Are both cars either ABS (only) or both ABS+traction control? They have to be the same to continue the operation of the ABS and/or TCS.

The e-brake mechanism and cable are different. I don't think the axles are an issue. The brakes mount to backing plates that attach to the ends of the axle housing.

raxxus

Ack, good catch. It's GU2 on the 99 TA Auto. Neither have Traction Control but both have ABS.

So I'll need to switch the backing plates then?

Injuneer

Take a look at both of the brake setups and compare.

rngilliland

Just a few things to think about. The 95 has a clutch type posi and the 99 is a Torsen posi. I put a 99 rear in my 94 and I couldn't tell any difference between them. If the 95 is a T56 the 2.73 rear isn't going to work very well. Both cars will need to have the PCMs programed for the gear change.

If you decide to swap them I would just swap the rear housing and keep everything else with the original cars. The axle shafts are slightly different lengths between the 95 and 99. I think this is to keep the calipers centered on the rotors with the different rear brakes. Everything about the two brake types is different so you'll need to swap it all. The easiest way would be to unhook the brake line at the body and swap everything with both rears out of the cars.

raxxus

The more I dig, the more I realize it'd just be easier to find a local ls1 rear end with 3.42 gears for the 99 and leave the 95 as is. They are in the range of 200-300 around here, with 30 day warranties.

Thanks anyways gentlemen.