Leaking Pinion Seal
 

I installed 3.42's last week and have put about 100 miles on them so far. I checked under the truck today and there is gear oil splattered on the underbody where the pinion is, there is also oil on the pinion yoke itself. No other issues, vibrations, or odd noises.

The oil appears to be coming from the inside of the pinion yoke where the nut and splines are, not the outside. I did replace the pinion seal with the one from the install kit. I reused the yoke and whatever that seal is that pressed onto it. I did not put any sealant on the splines themselves, am I supposed to? I didn't on my last gear install and it didn't leak.

Could an issue with the crush sleeve cause this? I have reused the stock sleeve twice because I cannot crush the new one, I've tried everything. The first time I reused it it didn't leak.

yes your supposed to put some sealant on the splines, not much but a smear at the least

why couldnt you crush the new crush sleeve?

I use Teflon pipe thread sealant, the paste not the tape. Don't use silicone.

No idea. I even bought a 640 ft-lb impact, that didnt do it. I used a breaker bar with a cheater bar with a floor jack under that, that didnt do it. I put the crush sleeve in the vice to get the crushing started, that didnt work. I dont have a shop press. The arbor press didnt do it either.

I have some of that stuff, I'll give it a try.

Does the seal on the pinion yoke actually do anything? I cant seem to one for sale that isnt already on a yoke, which are expensive!

"Pinion yoke splines - Sealant - P/N 12346004"

that's off Mitchell and I searched the p/n and linked it. aklowriderz71 was correct, its not silicone...my bad, I just saw "sealant" and grabbed silicone...well 8,000mi on mine (and not to mention the ones I've done at work) and no leaks so far haha :bang:

I'm going to tackle this today. I have some liquid teflon sealant to use on the splines. I'm also going to put some RTV around the washer, nut, and threads just to be sure.

I use red loctite on the pinion nut and I couldnt crush the new washer either.

Guys. You have to use a new crush sleeve. I really have to ask how you are installing these things. I have geared many axles from the 8.5/8.6, 9.5, and 14FF. I was able to crush the sleeves on all of these. It took effort, but I got it done.

An impact wrench wont always do it. You need a sturdy means of holding the yoke, and a good breaker bar with a cheater pipe. A 6 point socket is recommended.

Another tip, I use the old pinion nut to get the pinion bearing preload to about where it needs to be, and then use the new nut with locktite to set the final load.

Those oil seals have a little garter spring on the back side that likes to pop out. I normally pack the back side of the seal of vaseline so the spring doesn't pop out during install.

The crush sleeve could be the culprit. Since you reused it, there is a chance that you don't have the necessary tension between the pinion and threads even though you have the correct preload. If the pinion nut backs off, allowing the pinion to move around, there is chance that this movement could have damaged the seal. However, if that was the case, you would also hear noise and feel vibration.

That said, it is likely that the garter spring on the oil seal popped off. If I were you, I would get a new nut and crush sleeve on that thing.

Thanks for the info. But I cannot crush the sleeve, I've tried everything that I have available to me. I see your point on how it provides tension for the nut, something for the nut to smash up against. But it did take quite a bit of impact gunning to get the pinion drag correct, so I think the nut is plenty secure.

I packed the seal with vaseline to hold the spring in place, it didn't pop out when I installed the seal. Even if it did pop out, it would leak around the outside of the yoke, not through the center of the yoke like mine is doing.