GM /Chevrolet 4T65e transmission versions in vans through the years?

What is the differences in the 4T65e transmissions in minivans? Some web sites are saying i can swap transmissions, and other sites like jasperengines and rockauto are showing they are different part numbers for their stock and they will not be able to swap. The transmission in my '04 chev venture is dead with zero pump pressure and had been slipping in first gear for a while. Supposedly, according to different suppliers, only another 2004 transmission will work in it's place.

I can get a used transmission out of a wrecked '06 chev uplander locally for $200 and it has 120k miles . Both my transmission and the wrecked '06 are both 4T65e trans and 2 wheel drive versions with the 3.29 gear ratio. When i run both vans VIN numbers at the chev dealer parts dept, they both show the "M15" transmission RPO code on both vans, but the parts guy says they are "different" part numbers and will not work --- only no one seems to be able to tell me what is the difference is (internally or externally).

When i look at purchasing overhaul or rebuild kits for the 4t65e, they only sell 2 versions -- those up to 2002 and a different kit for those 2003 and up.

Any thoughts or differences in the 2004 versus the 2006 versions of the 4T65e? (other than the different torque converter for the 3.5L engine in the 2006 uplander)