Originally Posted by
Slo_E4
You need a dremmel. With a normal cutting wheel that comes with almost all dremmels. I would say wear the wheel down a little bit so it gets smaller. Becareful they snap very easily. Once it's small enough to your liking, make a notch in the hex head, and use a small flat head to turn her out. Hope this will help.
I'm guessing if he used an extractor on it then this is no longer an option. How much does the diff housing cost? Can you just cut it off and try to preserve the rest of the diff?