Just replacing the rear of the transmission housing will not resolve the problem here. You need to know what caused the holes in the transmission housing before replacing this part! As automatic transmission is over my head I would take this one into a trans shop for this part of the repair. The rest of the rear end should not have been harmed. You can check the drive line center mount by trying to move the drive shaft. The center of the drive line should not move more than a 1/2 of an inch or 13MM. Good luck John