toyota rear end seal question

I got a Toy rear end for my mazda and I took the bolt out of the rear end where the drive line bolts to the rear end. When I went to put it back together the seal slipped off the inside. Does anyone know how to replace the rubber seal on that part of the rear end?Do I need to pull the whole rear end apart or what.I looks like it was pressed in.Any help would be great.Ron