Borg Warner SG how to.

well, if you were that "type of guy", you'd buy a Factory Service Manual, and you'd do it yourself, instead of hiring it out to some guy who did it wrong.
For the record, I never said hammer directly on your axles, you hammer on a block of wood spanning the axle lug studs.
I do have the factory service manual but differentials is the only thing that makes me a little nervous working on. The guy that did the rebuild does nearly all the cars that run at the local drag strip and has done 2 of my other rear ends. This is the first I've ever heard of seen a mishap like this from his work.