Early-A Cross Member Swap-Easy in car?

Will a jack supporting the rear of the trans work, when swapping out the rear trans cross member? I got mine back from TTI (modified for an early-a with dual exhaust). I was going to loosen the trans mount bolt at the rear of the tail shaft after using a jack to support the rear of the trans, and then remove the 4 cross member bolts.
Yes aslong as the trans is still attached to an engine,the engine mounts will hold all of it up with a jack at the back of trans.:D