I have the same problem, 2 new seals and a new bushing it still leaks. My car originally had a 7 1/4 rearend which was removed for an 8 3/4, i was wondering if it could be the pinion angle or if the driveshaft was too short??
Same set up. I had a 7 1/4 to 8 3/4 however it never really leaked to bad or at all. Now It is. I have not changed the busing yet. The do make longer yokes to fix the problem. I might just pack it with major grease in the busing and new seal call it a day.