Have you tried a good machine shop that specializes in aluminum? They should be able to weld and repair and resurface whatever is leaking. Then you know what you have. Buying a different one will require brake work etc. Just a thought.
Thanks all for the input/ suggestions. I just purchased a differencial from a 05 manual ,so with a few changes I should be able to make it work. I figured I would have more $ in a repair if it could be repaired then just changing it out. The rear I bought comes with shocks, springs and control arms so if anyone needs any of those parts I will have them. By the way my diff was steel not aluminum.