I know that I could replace that seal, however, there is more serious problems going on in there. When I start from a dead stop and make a turn (especially to the right) I get some slippage and a clunk or two when it catches. It even does it sometimes starting from a dead stop going straight and every time I shift I get the clunk sound as well. This rear end has been going out for some time, but I have just been babying it. Now though it has 240,000 miles and is getting ready to retire whether I like it or not. I have had the motor out a couple times, done the clutch a couple times, done wheel bearings, done the brakes about a million times, but I don't know squat about differentials and what it looks like in there. What could be happening in there by what I have described here? Any opinions?