Rear Pinion Leak

[Dakarra]

HI All, I'm new to the forum, but I've had my 2021 Gladiator Willys 3.6L with auto trans since new. 2" lift, 35" KO2s, 4.88 Gears (added about 8 months ago), all suspension components upgraded including steering dampener, air bags in the rear springs. RSI Smart Cap, front and rear bumpers and a 12K lb winch. All in all I'm kind of heavy, but not as bad as many that I see. When I remind myself that it is not a true 1/2 ton I'm very satisfied with the performance overall, and hey it is fun to drive.

Took a trip from Fort Worth to Austin, highway speeds averaging 65-72 MPH. About 450 miles round trip. Didn't notice anything new, however I've had a slight wobble that I thought may have been tire balancing. Stopped for a bite just before getting home and saw 10-12 drops of oil under the rear diff. Ruh-Roh. Got it home and level and let it settle for a few minutes and crawled under with a flashlight. The oil appears to be coming from the seal where the rear drive shaft enters the differential. In searching around the 'net it seems this isn't real common but not un-heard of either. There also is some discussion about death-wobble, but I'm not sure that's what I've got - my wobble doesn't get worse with braking and tends to smooth out at various speeds.

I'll be checking in with the shop that did my regear Monday morning. I have less than 18K on the odometer but I think the 4.88 install voided the factory warranty.

Any of you more experienced folks seen this problem before? How common is it, and is the 'fix' fairly straightforward and (most important) reliable? Advice welcomed!

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[Escape.idiocracy]

Really depends on how bad the leak is.
to fix this correctly you will need to take the yolk off…. Which means new crush sleeve on the pinion. So, the seal is probably $15… Crush sleeves are also cheap $4-8….

I am sure there is a shop out there that will just pull the yolk and seal…. Replace and zip it back together… however your proper preload will not be set on the pinion any longer.


call the shop that did your gears and see if they will cut you a deal (and do it right)

 

[TheSolarWizard]

Improper torque on the pinion nut can cause this. Unless you have a seriously out of balance driveshaft this likely occurred during the regear and if the shop stands behind their work they should fix this.

its not going to be covered under factory warranty

 

[JTPatriot]

Not uncommon for seals to leak after gear swaps. Had that happen on after getting a set of gears swapped, shop that did the install replaced the seal then did not install the seal but started the crush sleeve crush then installed the seal and finished the install. His thoughts were maybe the jerking from the impact on the start of the crush was making the yoke "bang up" the seal.
I recently had to replace my front pinon seal, read all the pros and cons of the crush sleave. Ended up marking everything in there installed positions and noted how many threads exposed past the nut. Removed it all replaced the seal and went back to the previous spots and it has been fine so far. If one does it this way it is your choice, just letting one know that it worked for me.

I had a slight wobble at around 50 mph, exaggerated with uneven surfaces. Got the tires rebalanced and it fixed it. So try getting the tires rebalanced first.

 

[abe57]

If you are getting a Vibration vs wobble and does no happen at all speeds it might be a bad U-Joint cup going bad . Had this very problem with my Exterra 4x4 and it was just one cup in the rear u- joint that was bad .Would vibrate at around 35-40 mph above that would level out then at around 65- 70 mph it would come back and over 70 mph would disappear. It did wallow out the transmission tail a bit to where the tech installed a sleeve & seal kit . May or may not be your problem but just something to consider.

 

[Dakarra]

Thanks to all that have replied. It is leaking pretty bad and it is quite a mess underneath. I'm heading over to the shop that installed the 4.88 gears on Monday and we'll see what they say. I'll update the forum as it progresses.

 

[Dakarra]

Follow-Up: I had been refraining from saying who installed the 4.88 gears until I had a chance to talk to them about my leak - So I took it over to the folks at Dallas Offroad and they got my JT on a rack to see what was happening - yep, it was the rear pinion seal. They covered the whole thing under their warranty without hesitation or delay. I've had it back for about 24 hours now and so far - all is well. Can't say enough positive about how the guys at Dallas Offroad jumped on it and made it right. Thanks to all for the suggestions and guidance! ~dk

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