Front and Rear Pinion Seal leak

KY_Jeep

Member
So I installed a set of Yukon 4.88s with ARB lockers front and rear about 1000 miles ago on my 2010 Sport. (yea I know, don't waste money on the 30....) The install went well, broke the gears in per Yukons instructions. After the break in, took it out for some light wheeling to test the lockers. Worked perfectly as it should. Now about 1-2 weeks after that I have a leaking front AND rear pinion seal. Of course all this was new with the install kit. The front is a much worse leak as it will actually leave about a half dollar size spot on the garage floor and the rear you can tell is just seaping out. Any thoughts on why both would leaking after doing ok to start? The axle vents are clear and no other issues that I can see.
 

WJCO

Meme King
If a shop did it, take it back. If you did it, endure the fluid levels aren't overfull. My guess is that the seals were either damaged during install or RTV wasnt put on the outside diameter of the seals.
 

kbsvo2go

New member
Did you use silicon on the yoke splines? I've seen oil migrate up the splines and leak out from under the pinion nut which eventually collects on the yoke right at the seal. I would clean it real good with brake parts cleaner and go for a short drive and inspect. If it's dry inside the yoke around the nut and only leaking at the seal then that's definitely your leak.


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KY_Jeep

Member
Did you use silicon on the yoke splines? I've seen oil migrate up the splines and leak out from under the pinion nut which eventually collects on the yoke right at the seal. I would clean it real good with brake parts cleaner and go for a short drive and inspect. If it's dry inside the yoke around the nut and only leaking at the seal then that's definitely your leak.

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I did not seal the splines as I have never had to (guess that's going to change now) , I don't really feel like they were installed correctly, especially since both are leaking. What are the chances of being able to seal the splines without taking the pinion nut off?
 

WJCO

Meme King
I did not seal the splines as I have never had to (guess that's going to change now) , I don't really feel like they were installed correctly, especially since both are leaking. What are the chances of being able to seal the splines without taking the pinion nut off?

Not going to happen. Unless you use Flexseal or something and coat the whole area. You should clean it off first and see where the leak is coming from. Did you do the gears yourself? How did you torque the pinion nut and what was your final preload reading?
 

Slimebones

Active Member
Not going to happen. Unless you use Flexseal or something and coat the whole area. You should clean it off first and see where the leak is coming from. Did you do the gears yourself? How did you torque the pinion nut and what was your final preload reading?

I see what you did there. QC.:idontknow:
 

KY_Jeep

Member
Not going to happen. Unless you use Flexseal or something and coat the whole area. You should clean it off first and see where the leak is coming from. Did you do the gears yourself? How did you torque the pinion nut and what was your final preload reading?


My dad and I did the gear/locker install. He is a 30+ year ASE Master tech. The pinion was torqued with a ratchet and checked with an in-lb torque wrench. I believe the pre load was 14-15 in-lb. 15 being the max per Yukons instructions. A new nut was used as well.
 

WJCO

Meme King
My dad and I did the gear/locker install. He is a 30+ year ASE Master tech. The pinion was torqued with a ratchet and checked with an in-lb torque wrench. I believe the pre load was 14-15 in-lb. 15 being the max per Yukons instructions. A new nut was used as well.

Sounds legit. I would just clean it up and recheck. If it is leaking from a small area, you may be able to just spread some rtv on there.
 

KY_Jeep

Member
Well round 2 of this thread. Installed new front pinion seal, applied RTV to outer seal edge and sealed splines. About 2 weeks or so in and got another leak, Not as bad as before but it's definitely an issue. This was replaced with a Federal Mogul seal. Any thoughts?
 

WJCO

Meme King
Well round 2 of this thread. Installed new front pinion seal, applied RTV to outer seal edge and sealed splines. About 2 weeks or so in and got another leak, Not as bad as before but it's definitely an issue. This was replaced with a Federal Mogul seal. Any thoughts?

Any chance there's a score mark on the yoke causing the seal to not seal? Is it leaking where the seal touches the yoke or where the seal touches the housing?
 

KY_Jeep

Member
Pinion looks and feels good. From what I can tell, the seal looks to be leaking at the very bottom on the outer lip. The seal has a 3 year warranty so i guess I will replace it again and recheck and reseal everything.
 
J

JKDream

Guest
Well round 2 of this thread. Installed new front pinion seal, applied RTV to outer seal edge and sealed splines. About 2 weeks or so in and got another leak, Not as bad as before but it's definitely an issue. This was replaced with a Federal Mogul seal. Any thoughts?

I'm assuming you did, but I'll ask anyway - did you change the fluid on the break in?
Some gear sets will have small metal shavings that come off during break in that will shred seals very quickly.
 

KY_Jeep

Member
I'm assuming you did, but I'll ask anyway - did you change the fluid on the break in?
Some gear sets will have small metal shavings that come off during break in that will shred seals very quickly.

Yes, fluid was changed at the 500 mile break in.
 

Jody Treadway

New member
This happened to me a few times with Yukon and other aftermarket pinion seals. Now I primarily use OEM quality seals and have had much, much better results.
Once you hold the 2 different ones in your hands the difference in quality is substantial IMO.
 
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