buick rendezvous transmission interchange

i have the wrecked 2005 rendezvous kicking around with a super low mile trans rebuild that cost me an arm and 1.5 legs. i've been keeping an eye out for another with a bad transmission to make a good working vehicle on the cheap that can be kept around as a backup or flipped for profit.

found a 2004 that is identical drivetrain layout other than year. same 3400 engine, FWD. but when i search car-part it shows only 2004 transmissions for 04's and 2005 for 05's and doesn't show the other when i search. i find it hard to believe that the 05 would not work in the 04, but gm does some strange stuff with the same model of transmission in the same years let alone year to year.

does anyone have any kind of interchange info? i asked the transmission shop before i had the 05 trans rebuilt and he said it should work but wouldn't promise anything as i had an 04 trans on the shelf. or course that one is no longer around as my dad's neighbor bought it.

i enjoy the utility of the buick and wouldn't mind having it around especially since the wrecked one is sitting here with new trans, rack, brakes all around, front struts, rear shocks, and tires. have a nice trailer hitch sitting here and we even have a rebuilt gauge cluster for an 04 since they get wonky after a while.

I know my wifes 04 saturn has a one year only transmission. Maybe gm did the same crap with the buicks? Hers is the 5 speed auto.

I think it has to deal with the pcm change around that time. The change brought about slightly different programming logic. This brings about the lawyers and if you say it's "the same", you're on the hook for saying it's the same when it may not be the same. Sad part it maybe as simple as a different plug for something too.

I have no interchange info...BUT I do have a 2006 FWD Rendezvous 3500 and a 2004 AWD Rendezvous 3400 and would be happy to put either of them on ramps and take photos of anything (mounts, sensors, harness, etc) if that would help you in any way.

i appreciate the thought. the transmissions and vehicles are physically identical, it is the computer that has me concerned. i'm not sure what they changed, but i know that i can tune the 04 computer with hptuners but they have no support for the 05, so something changed. i just can't get a straight answer exactly what it is. i know when i put a 1991 4T60E/3.4DOHC engine in a 1994 car with the 94 engine harness, it was as simple as taking the pinouts for both transmission plugs and switching the wires around to work.