I got my differential all fixed up last Saturday, put the Yukon 4.11 gears in and everything went smoothly accept since then my pinion has been leaking like crazy and the drive shaft is throwing gear oil all over the under side of my pickup. We replaced the seal once already but it is still leaking. What are some options I have in order to fix this rather than just replacing the seal constantly. My friend just mentioned to me that maybe it's just over filled, could that be the culprit? I can take some pics of it tomorrow morning.

 

well, you should be able to fill it to the bottom of the fill hole without leakage, as that's how I do mine and it doesn't leak. Not sure how you'd manage filling it more than that, so I suspect you'd got a problem in your install procedure.

 

Only way it could be over filled, would be if the rear was up on jacks and a lot higher than the front obviously(But, it still should not leak). I have to also say, something went wrong with the install.