Thead

The very last bolt in the cross member is getting stripped every time i try to loosen it. I'm gonna try an impact wrench tommorow. Is it possible to get the mount off without removing the crossmember ? THanks.

N/A

Are you referring to the H shaped brace that supports the transmission at the mid point? You'll want to drop the brace in order to get the mounts changed. If it is stripping out it was likely cross threaded when it was put in orignally. In which take it to the dealership and have them fix it. They will have to likely rethread the hole with a larger bolt/thread size.