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03 Regal gs trans question.

Swiggles

Swiggles

Donating User
I have an 04 impala ss with an 03 Regal gs motor and trans. Can I simply swap in a 98-02 gtp trans? Is there a problem with the engine wiring harness that I could simply repin or is there more to it than that?
 


you would need to do the pnp swap, google that with billboost37, the how to comes up.......or grab him, your local enough.
 
If you look around more, you should find a few posts by Dave at TEP that the VB etc are quite different on 03 vs any other year. 04 and up was different than 98-02 and 03.
 
But is that just the Grand Prix or is all of them in those years? I don’t really care about the differences inside if it’s just put the trans in, plug in the connectors, fill with fluid, and go. Or do I need to change things? I have to double check but I think there is already an external pnp switch on my impala’s trans.
 
Brian.. it's not supposed to work. I didn't do a swap ever with an 03 using anything but an 03 for that very reason. Never really dug into it though. Dave and others said 03 was the unicorn year and that's in all cars. First heard about this on Bonnevilles, and it applied to all platforms with the 4T65. Might be worth a call to TEP to triple check though.

Here's what I do:
If you have a 97-02 use a 97-02
If you have an 03, life sucks use 03
If you have an 04-08 use 04-08
 


BillBooost37 said:
Brian.. it's not supposed to work. I didn't do a swap ever with an 03 using anything but an 03 for that very reason. Never really dug into it though. Dave and others said 03 was the unicorn year and that's in all cars. First heard about this on Bonnevilles, and it applied to all platforms with the 4T65. Might be worth a call to TEP to triple check though.

Here's what I do:
If you have a 97-02 use a 97-02
If you have an 03, life sucks use 03
If you have an 04-08 use 04-08
Click to expand...

I see what you did there.
 
Alright so I don’t have a pnp switch :( . Now if I get an 04 impala ss engine wiring harness can I use the 98-02 trans? Or it needs to be an 04-08 trans?
 
short answer the shizzle inside is too different. If you wanna put a pnp on a non pnp trans.. it's cake. If you wanna use an internal vs external, that's cake too. The problem isn't wiring. It's that they changed from an apple to an orange There's differences that the pcm etc may say.. go pound sand.

Obviously.. you can drop it in and give it a try. Remember this though.. Derek aka BobC's brother. He put a W body trans in his Riv and the rear trans mount support webbing wasnt there. He didn't make it around the block before the case cracked and he was pushing a 5000lb Riv home. Spent the moola to have Claudio's trans guy put those guts into the right case and ... then that worked. There's some stuff we can't quite get around no matter how much we hope it's going to work.
 


Lol I’m sure I have one on the parts trans in my garage.

So I need to swap out the internal wiring harness? Or the valve body and other stuff too?

Currently I have an 04 impala ss with motor/trans from 03 Regal gs according to the papers I found in the car when I got it. Pcm is the stock 04 impala ss one that I tuned. I had to change the reluctor wheel settings or whatever it’s call in the tune for the trans to shift right. I don’t know for sure which engine wiring harness I have, I think is from the gs because it doesn’t fit quite right a couple spots.

04 impala
03 gs motor/trans
04 impala pcm
Wiring harness?
 
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Do a bit more searching, I forget if it's 04+ or 03 that someone swapped a couple of wires at the trans in order to use it. I do know that from 98-02 vs 04-08 you do have to change out the valve body/channel plate and wiring plus the pump shaft in order for it to work. Otherwise most of the parts are swappable.
 
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