Leaking Rear Differential?

vucelick · December 22, 2009

I was changing tires the other day and noticed that there is a light coat of oil on the front underside of my rear differential. It is not leaking from the rear cover, and it really does not look like it is the pinion seal. It almost looks like it is leaking from where the axle tubes are pressed into the center section. Any ideas? 2500HD 8.1

JoJoJim · December 30, 2009

A thought is that the filler plug went bad on mine and let oil spread all over the place. I think is has a plastic or rubber seal on it that has to be in place. Just an idea.

Nothing looked wrong with the old plug but it did leak just enough to make things messy.

vucelick · January 6, 2010

Thanks, I'll check that, I am leaning toward leaking pinion seal.

vucelick · January 15, 2010

Solved! found the dreaded pinhole in the transfer case was leaking and spraying trans fluid all over the underside of the truck including the read differential. Bummer, guess I'll be buying a new case half (or repairing this one if I can find someone to weld magnesium), and the kennedy diesel pump rub repair kit.

steiny93 · January 18, 2010

Solved! found the dreaded pinhole in the transfer case was leaking and spraying trans fluid all over the underside of the truck including the read differential. Bummer, guess I'll be buying a new case half (or repairing this one if I can find someone to weld magnesium), and the kennedy diesel pump rub repair kit.

give jb weld a try, if it doesn't work you aren't going to be out anything

jsboening · January 18, 2010

I had the same issue with mine. Only I ended up buying a new diff cover before i figured out it was the trans case. I was lucky I caught it before any damage was done to the transfer case internals. I had mine welded up at a local John Deere dealership(Thanks Jim) and used the Kennedy Diesel kit. Worked great and easy to install.

vucelick · January 19, 2010

Decided to go with a new case half, as I read something about magnesium being very difficult to weld and needing to be stress relieved after welding. I ask all of my local nuclear certified weld buddies and they said it can be done, but none of them were set up for it. The new kit will be here Thursday, luckily I caught it before any damage occurred to the T-case.

Mortgage Paul · September 14, 2010

Rub kit?

What rubs? Anyone have pics? I dont see anything rubbing on any of our GM's,.

Shawn T · September 15, 2010

Solved! found the dreaded pinhole in the transfer case was leaking and spraying trans fluid all over the underside of the truck including the read differential. Bummer, guess I'll be buying a new case half (or repairing this one if I can find someone to weld magnesium), and the kennedy diesel pump rub repair kit.

I have the same problem, driveline flinging fluid everywhere and I had a mechanic check it out while doing other repairs and he said pinhole in the output shaft? I have tried to physically see it, can you tell me where I should be looking because it is sure making a mess of things under the truck and in my garage.