Engine and Transmission Compatability

**slednut** · 02-09-2009

Hello, I just bought a 2000 gtp with about 314000kms on it. Car it self looks new and it very clean and the engine is a good runner still. But the transmission shifts funny between 1st and 2nd when i am accelerating moderately to full throttle. It take about 4 seconds to complete the shift. It doesn't seem to really slip and it doesn't drop into second either. I did a flush and filter change but no difference. I am not to worried about but it, but it is the basis of my question. I have an opportunity to buy a wrecked 2000 Grand Prix GT for fairly cheap. Are the engine and transmission able to swap. I mean i would have to change the supercharger over, but I am not afraid of that. Just wondering what/if their are differences. Any info and help would be appreciated.
Thanks
Ryan

TDCRacing · 02-09-2009

The main differences between the two transmissions are the differential. The non GTP cars (GT) have the non HD differential. Also the passenger side axle is different I belive.Everything else will bolt up fine.

**Sabrewings** · 02-09-2009

He'd need to take the flywheel off the GT engine so the tranny will bolt up. The HD and non-HD use different TC bolt patterns.

TDCRacing · 02-09-2009

Good point.

**slednut** · 02-09-2009

So... I could switch the final drives and flywheel and it should work just fine. What about engines though. The one i can get only has about 140000km on it.

**Sabrewings** · 02-09-2009

Originally Posted by slednut

So... I could switch the final drives and flywheel and it should work just fine. What about engines though. The one i can get only has about 140000km on it.

No, you can't just switch the final drives. The non-HD tranny will have a FDR of 3.29 with either the non-HD diff or the HD diff. So you'll need to get your PCM programmed for that FDR to use that tranny. The only other option is to dig into the side cover and swap the chain and sprockets from the HD to the non-HD. That will give you the 2.93 FDR that GTPs have.

TDCRacing · 02-09-2009

You could keep the 3.29 gears that is in the non-HD transmission and just swap the whole transmission over. But pcm changes will be required. 160 bucks max. I would do it if it was me. If you want to have a lot more get up and go.

You can also swap the top (from the heads up) of you're GTP engine and put it on the engine you're getting. The compression ratio is higher. But GENERALLY speaking you should be ok. That should also give you an increase in power.

What I would recomend is doing that....Then get the pcm tuned for that as well....Take care of both the gear change issues and the top swap issues (if any)