Thanks - that's good to hear. Hopefully this is just a fluke. The truck drives fine, no issues that I know of.

 

Looks to me like the seal was not properly installed at the factory. Very rare (like never) for one to "back out" on it's own the way yours appears.

 

Not heavy but pulled about 5k for 2300 miles in April and it hasn’t leaked a drop. Getting ready to roll over 19k miles on the truck so close to you on mileage.

I’ve seen a few posts about the rear output shaft seal leaking so we’re not alone. Maybe a bad batch of seals?!? Mine was built in March/18.

 

Mine was built October of 2016, so I don't know. Also not sure why it started spraying oil only in the last couple of days - at least, so I could smell it. Pretty sure I would've noticed it before this if it's been doing it the whole time...?

 

The dealer confirmed the seal needs replacing and will be doing so under warranty. Happy to say they think the new seal will be here before the weekend so I can use the truck over the long weekend for hauling the TC.

 

my 2013 is dry as a bone.

 

I'll have to check mine.. I get a whiff of something every now and then and haven't traced it down yet.. but haven't crawled under it either.. and mine was built just after yours, just before Thanksgiving 16.

 

Good to get under the truck now and again to make sure all is well. Apparently on the larger Super Duties you also want to keep an eye on the rear differential seal.

 

ps. And again, I just have to give my dealer a huge shoutout - they continue to take great care of our vehicles.

 

Looks to me like it's been leaking for a while based on the dirty oil stain. A little oil will go a long way but it takes some time to accumulate some grime. Doubt it was low on oil. How many miles?

 

16,700 miles on the truck. We live down a half mile of dirt road and she's my daily driver. We also just did a few hundred miles touring our great state with the TC. Plenty of which was down dusty dirt roads. I only smelled that aroma after the trip and after hauling water. I tend to pay close attention to my equipment - pretty sure I caught it relatively quickly.

 

I don't think that's a seal. It spins with the driveshaft. My '19 looks exactly the same and hasn't leaked a bit. What looks like a seal in the picture is probably there to keep things out of the seal that wrap up around the u-joint.

 

That flanged part on the seal isn't supposed to be flush up against the body of the transfer case?? I don't see how that can spin with the driveshaft. And in my case, then where is the oil coming from?

 

Block your tires and put the trans in neutral. I bet if you wiggle the driveshaft you’ll see the “seal” wiggle with it. Just look at your picture, it’s hard up against the yoke. Mine is exactly the same. If a seal was spinning in the housing it would get very hot in short order and wouldn’t be so shiny and clean looking now.

 

Well I'll be. Seals sure are a lot different than the late 80's, when I was doing a bunch of wrenching. The dealer agreed that's where the oil was coming from and agreed that seal needed replacing. I'm going to have to research how these work, how far into the case housing they extend, and how/what/why they fail.