Okay, the tapping I thought that was the tranny was diagnosed by the Subaru dealership as the rear pinion bearing. They told me that the only way to get it fixed is a new diff AND drive shaft. $2500!! Now I dont know tons about this car, but my 70 Chevelle rear end is very similar, and I built that and it is bullet proof. I dont understand why I cant just replace the pinion bearing and put it back together. Anyone have any knowledge on the inner workings of these rear diffs??? Please help!