Thanks for the offer - The gear shop I brought the diff to couldn't locate a case, so they ordered the case from the mfg - who made them for GM, I was told. I should have indicated that my '99 sub is a diesel. I know the gear shop was pretty adament (sp?) on getting the correct right side half of the case, wanting to know the axel tube size or tube case number . . . That's why I brought the whole thing to them, to ensure the right part the first time. Lot's of 3.73 off gas jobs around. Again, thanks for your time.