Rear differential pinion seal leak?

lapoolboy · July 31, 2020

Noticed this "damp" looking area at the front of the rear diff. It isn't wet really, but looks like there's been some slight seepage of oil at some point. Truck is under warranty, so I guess I'll have them check it out as bad as I hate to be without my truck. Anyone else noticed same issue or have had the seal replaced? I park in the exact same spot every night and there is nothing on the concrete below.

CamGTP · July 31, 2020

I've had previous vehicles do that before. I've cleaned them up and it never really came back in the time I owned them. If that was my truck I would do the same thing, clean it up and see if it ever comes back. The less people that touch my stuff the better.

blazerk5drew · August 5, 2020

Had this happen on my 19 at about 10k miles (Actually was dripping). Seal was on a nationwide back order so I had to wait about 1 month before the parts even came in. I am also very hesitant to let other people work on my vehicles. I made sure that a driveline tech was performing the repairs and pre-loading the pinion bearing correctly. Seal replaced under warranty. No issues 15k later. I would also pay close attention once the repairs are performed to make sure the rear axle isn't whining from over tightening of the pinion nut. I have seen people drive these on with an impact gun not understanding what they were doing.

That being said, the amount of oil on that seal is about a drop worth. As CamGTP stated, maybe clean it and keep an eye on it. If you start to see oil splattered around the gas tank area, probably time for a seal. I also found that the factory fill level was way low. I check all fluid levels when I first purchase a vehicle.

Steve Barnett · July 3, 2021

I have a 2017 gmc with only 20 k miles , mine leaking on the garage floor . this seems crazy to me, that a new truck would leak . I had a 1994 Chevy with a 170000 miles and never leaked a drop.

CamGTP · July 3, 2021

It's a seal failure, stuff happens. I mean they only made like a few hundred thousands seals for GM trucks, it's bound to happen to someone.

If stuff was perfect everyday all day, no body would have a job in the service industry.

Grumpy Bear · July 4, 2021

At 20K miles mine looked like this. Shaft was fine. The rubber lip was good as well. But it fit loose in the housing. GM was a weeks wait so went to a local bearing house, part in hand (numbers) and got a National replacement then smeared it with RTV before setting it. 123K miles later dry as desert bones.