been told that if u have a 99 grand prix the tranny has to be out of a 99... true?

[wgnbrnr83]

i have a 99 grand prix with a 3.1L and a 4T65e... the code on the tag is AH i have found a trans out of a 01 with RMD on the tag. i was jus wondering if it would work cuz i have talked to a couple transmission shops and they keep telling me that it has to be out of a 99. another question would be are all the electrical connections the same between the two. i know the gear ratio is different in 4th gear and everyone keeps tellin me that it would end up goin out

[Slick2500]

The only problem you might run into is different cooler lines from the trans but iirc you can get adapters for them.

[ZR1Vette09]

^what he said

[wgnbrnr83]

what about gear ratio? i know that some of them have different ratios and wass told that if the gear ratio is different than the 99 that it will throw a code and it wont shift.

[Slick2500]

The computer can be reprogrammed to accept the different gear ratio, unless the trans is out of an 04+ or a GTP the gear ratio is the same.

[TLSheff]

Specifically for a 99 GP with the 3.1L my computer shows

W body - 3.1M (L82), 4-SPD AUTO TRANS (M13), 3.29R (FR9), (CODE 9AHW)
GM # 19178438

The GM Part #19178438 spans the lot of 1998 & 1999 Lumina/Monte Carlo, Grand Prix, Century/Regal group. The Case Code will change accordingly, but the Part# will still be the same tranny, and SHOULD match up with the same 3.29R gear and wouldn't need reprogramming

Hope this helps