Will a 04 transmission for a Pontiac Grand prix gt bolt up to a 05 motor

I called a transmission place and they told me they are different

Not that I know of, I can't see what is different, Did they say what?

No actually they didn't but I can buy the 04 whole car for 900 motor and tranny are good and will the doors and finders and all that mach up too

I drive an 04 Pontiac and I have purchased a few parts from an 05 and they fit great...

Transmission for sure though

I think it will, how about this, check with another tranny shop and see what they say, maybe even call two...

Yes, make sure before you spend money on something you can't use. It may be something as small as an electronic incompatibility, but if it won't work, it won't work. Manufacturers make small changes from year to year and it becomes more and more important to get the exact year and model part. Just because it will bolt on doesn't mean it will actually work.