Thread: Trans upgrade - '97 Regal GS into a '98 GP GT?

I have been doing research to see what is needed and if it'll work. I have some Q's, hoping you guys can answer/clarify. There is one local for the right price.

1) Will this transmission bolt up to my '98 GP GT and function without a tune? Is it safe to drive until it gets tuned?
2) Will the stock tq converter work from the '97 or even the '98?
3) What style cooling lines are on the '97s? (pin on, etc)
4) Is there anything NEEDED to make this work?

I am slowly doing a GTP swap to the card (still need some top swap items). My 4th gear is shot, and the trans is probably due for a rebuild. Not really looking to spend a fortune on trans work right now, so going used cheap and certified.

Thanks!

It will need a tune to work. I wouldnt drive it without a tune.

Otherwise its a straight swap pretty much.

Actually sometimes you get lucky on the gear ratio not getting pissed off and setting a code. You'd have to drive to to find out. You'll know quick if it starts bang shifting by setting code P1811 max adapt shift and gear ratio codes.

It will bolt right up. Ensure you match the flexplate to the torque converter. Meaning either 245mm or 258mm. NA should be 245 and SC should be 258.
As for the cooler lines. They should thread right in w/o issues.

To make it successful.
1. I'd program the pcm. You might give it a shot if it's not your primary vehicle though.
2. I'd ensure I used a 258 flex with the SC converter or a 245 with an na converter.

Keep in mind that no NA cars came with this trans, so likely you'll find that you need to alter the shift points etc based on load and available power.

5FDP - Thanks.

BillBoost37 - Always a pleasure when you give trans info. This is exactly what I needed to know. So I can re-use my verter or use the SC verter (if it even comes with one), as long as it uses the correct corresponding flywheel for each. Sounds pretty straight forward. Is there a benefit to using one over the other besides what appears to be size/rotating mass?

My goal is to have the thing tuned after the GTP swap via HP Tuners at a local reputable dyno shop, but I think I may pursue a mail order from 3800perf or ZZP just to stay safe. Anyone else I should look into?

Also, I am trying to put #'s together that I found online about these trans' gear ratios. Finding my current trans isn't hard, what I am having problems with is finding the '97 GS ratios. Any idea what they are or where I can look?

97 GS ratio is 2.93, it's the same as all (except CompG) charged 4T65E's. Aka the HD version.

I'd probably go local shop vs either of those tuners.