On my Saturn sw2 on the passenger side cv shaft it goes in an assembly that looks like a carrier bearing and them a solid shaft comes out the other side and goes in the transmission. What is this really and can it go bad.

That's exactly what it is. It's there to support the pass side axle because it's much longer than the drivers side.
It's possible to go bad, but rare.
If you were to buy the axle shaft for the pass side, then that bearing would come with it.