Leaking pinion seal-----clogged vent hose??

[edwx]

About a year ago a buddy of mine and I replaced the front differential pinion seal because it was leaking. The leak stopped. A couple of weeks ago, all of a sudden I noticed drops of oil on my garage floor under the differential. I was hoping it was coming from the diff cover, but no way. The seal is leaking again. Is it possible the diff vent is clogged and forcing the seal to leak? Hard to believe 2 seals would fail. We used a NAPA seal for the replacement. Thanks. Ed

 

[edwx]

I checked the vent tube and it looks ok. Didn't completely remove it or anything, just gave it a good looksee and it appears to be fine. the only thing I can think of is that there must be a rough spot on the flange that wears out the seal.

 

[SBV45]

I checked the vent tube and it looks ok. Didn't completely remove it or anything, just gave it a good looksee and it appears to be fine. the only thing I can think of is that there must be a rough spot on the flange that wears out the seal.

That or you have a bad pinion bearing that allows some slight movement of the shaft while rotating.

 

[rookieshooter]

I agree about the pinion bearing. Try grabbing the pinion yoke and see if there is slop. Also I'd remove the vent hose and try to blow through it and then check out the nipple from axle tube by sticking something through it just to make certain.
Are you hearing any axle noise that may have increased in the last few months? Are you putting any rtv on the seal?

 

[PEAR0119]

My truck was leaving nice baseball sized oil spots in the driveway from the differential area, so I brought it into the dealer since I have an extended warranty. Turns out that it was in fact the pinion seal that was leaking. I don't know if this is a common failure on these trucks or I in fact also have a bad pinion bearing.

 

[edwx]

Thanks for the feedback.

Last year when we tapped in the new seal it was a tight fit so it never even occured to us to put any rtv on it.

Pinion bearing? Sounds like a good possibility since the leak started all of a sudden. It went from nothing to drops. The seal leak I had last year was different from this leak. With the leaky seal, oil was slinging all over the place, especially across the oil pan, from the spinning of the yoke. This leak is NOT slinging any oil. When the truck is at rest, a few drops of oil just run out of the yoke area and run down and drop off the bottom of the diff cover. So that leads me to believe it is the bearing. The truck aslo sounds a little noisy, but I didn't know where it was coming from. It's not the wheel bearings because there is no noise difference when I turn side to side.

How much would the dealer charge to fix the bearing? I'm not even sure where the bearing is. Is it in the pinion flange or in the diff? I'm not up to doing this myself. My buddy with the lift and good tools is not available. Thanks. Ed.

 

[edwx]

Ok, so I broke out my repair cd, and found the location of the pinion bearing. Fortunately they all look like inexpensive parts....bearing, seal, new nut. Now the only ? is how much will they charge to do it. Hopefully I can get a 2 for one deal with the bearing and new seal seeing as they are both in the same spot. To be continued......

 

[rookieshooter]

I would at least for now try re-tightening the pinion nut. I've had to do mine a couple of times when I had the 8.8 in the rear. This helped in the noise area. Plus a loose pinion nut can make the pinion run out of round also causing the seal to leak. Use a large pipe wrench on the yoke and then put an extension (pipe) on a breaker bar or ratchet and snug it up pinion nut. If it moves easily it was too loose. Correct way would be to use a torque wrench.
I've alwaysed used rtv cause one can scratch the seal surface when removing and I've never had a leak and i've done a bunch.

 

[edwx]

Never did figure out hoe to get the vent hose off. Wasn't sure if it came off the nipple, or if the whole nipple/plastic thingy came out of the diff.

Anyway, against every screaming pore in my body I brought it to the local dealer to take a look at it. Initally they included 4 qts of diff oil in the estimate @ $25 per. So when I told them I would top off my own fluid, the estimate was about $134 for a new seal. When the got the yoke off they noticed that it was scored pretty badly, causing the leak (?), and hit me up for a new one. All in all I feel fortunate to get out of there for $194 including a new yoke, seal and inspection. Saved myself a bunch of time on my back. They gave me the old pinion yoke/flange and it's definitely scored. As soon as photobucket gets their act together I'll post the photo.

 

[rookieshooter]

Glad it's fixed, and not a bad price either. But what caused the scoreing? Wonder if it was from the first seal that went bad and got some grit in there? Then is the new one going to fix the leak with a scored yoke?

 

[edwx]

They put a new yoke on.

 

[rookieshooter]

They put a new yoke on.

Should have read your post better.

 

[edwx]

So I went to top off the diff fluid (It was down only a few ounces) after the seal replacement, and the plug was about halfway out, I could easily turn it with my fingers. So I topped it off and went back to the dealer and had a private conversation with the service manager.

 

[edwx]

Here's the yoke photo

Check out the wide score ring around the flange. Not sure how deep it is but you can definitely feel an indentation when you run your finger over it.

 

[Town]

Looks like the seal wore a path, probably with the help of debris in the area.