I was hauling around 11,000 pounds yesterday and when I got home I noticed that the rear differential was leaking oil. It looked like it blew it out the top somewhere while I was towing. The oil was all over the bottom of the bed and on the fuel tank. What could have caused this? Too much fluid? Seal leaking? Thanks for any help.
Clay

Update, I took the plug out of the differentail just now and the oil was foamy and was coming out of the plug hole. Is this a sign of wrong oil placed in the differential or that water has be introduced in the oil somehow?

 

Check the vent and make sure it is not plugged---towing that much would create a lot of heat which would create pressure in the diff, and if its not venting, the pressure has to go somewhere, and it usually goes out the pinion seal.

 

I have seen them many of times blow out a wheel seal. I would check to make sure it is venting, then replace the fluid with some fresh clean. and you should be all set after doing that!!

 

Towed the same amount again today, and the same thing happened. I checked the vent this weekend and it was not plugged. Could the Diff have too much oil in it? When I checked it this weekend it was foamy?

Clay

 

How many miles on the fluid and what kind of fluid do you use? Do you have sure grip?

 

Bought the truck with 50000 on it. I have never touched the rear end, my mechanic hasn’t either so im not sure what kind of oil is in it. The truck now has 88000 on it. I think I might change it completely and see what happens

clay

 

What "I" would do is pop the cover off, clean out the housing with some good brake cleaner and refill with 75-140 synthetic. If you have sure-grip be sure to add one bottle of the MoPar friction modifier too! I'm also a fan of the MoPar gray "gear lube" rtv to seal the cover.