Thread: Will a 03 gt trans work in my 99 gtp

Found wrecked 03 gt with 130k and was gonna get the trans for my gtp. I know the gtp trans have hd differentials and the gears are different ratios. I was wanting the 3.29 gears anyways. But what all would need from the 03 car? I was gonna have a shop swap them out.

you need the new gears tuned into the pcm. and maybe put the external pnp switch deal on the 03 tranny if its internal on the new tranny.

probably the tranny cooler lines will need to be swapped over too.

I was eventually getting tuned. Will it have to be tuned before it's drivable?

Originally Posted by pontiacGTP123

I was eventually getting tuned. Will it have to be tuned before it's drivable?

YES.

Ok thanks

it will drive, but can shift late/hard and so on and maybe damage it doing so, best to send the pcm out or get another pcm and send it out to be tuned.

that way you have it when the trannys done being swapped.