[Redog]

OK first the Tranny from the Van (4T65) will fit the engine on the Alero, however there is a lot of fab work required on the body/sub-frame end of it

The Alero has the 4T45 transmission in the V6, the 4 bangers got the 4T40 tranny. Same case, same tranny, but I'm willing to bet the internals are different.

The V6 Grand Am uses the 4T45 transmission with a 3.05 FDR, just like the Alero.

The Grand Am GT uses the 4T45 transmission with a 3.29 FDR.

The 3.61 FDR is used in the G6 V6 and the 4 banger gets a 3.90 FDR. Don't know if this is a direct swap due to mounting points in the body/sub-frame

Swapping in a GAGT Transmission is a direct swap, UNTIL you start driving it. All the gearing is the same but the FDR is different. Therefore the car's PCM will have to be reprogrammed with the correct FDR

Thank you and good nite