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-   -   IMPORTANT: Changing front differential oil (http://www.jeepgarage.org/f181/important-changing-front-differential-oil-4459.html)

RedRocker 12-02-2009 07:04 PM

IMPORTANT: Changing front differential oil
 
I just got my WK back from the dealer after a one month endeavor. I originally took the WK in for whining front gears. Chrysler doesn't allow (US) techs to rebuild axles so the dealership replaced the front axle. 10 miles later I was stuck on the side of the road with a frozen front axle. Dealership replaced the 1st replacement axle with a second replacement axle, that replacement axle froze during the tech's check ride. Dealership had a Jeep engineer come in to look at the problem. Here's the deal:

The problem was oil not getting to the rear pinion bearing, causing it to heat up and fail. This bearing does not sit in oil, so an oil path (or paths) is (are) designed into the housing. There are two possible causes for oil not getting to the bearing:
1. The housings were improperly machined, preventing the oil from getting to the bearing.
2. The axles come from the factory filled with oil. It's possible that there's not enough oil installed at the factory to properly lubricate the rear bearing. It's also possible that the couple degrees difference in pinion angle required of the 4" Superlift, combined with the bare minimum amount of oil installed by the factory, prevented proper lubrication.

Bottom line - GO Jeep in Golden, Colorado is great and....

If you ever have the front diff oil changed in your WK, MAKE SURE YOU OVERFILL THE DIFFERENTIAL.

Scottina06 12-02-2009 07:44 PM

Re: IMPORTANT: Changing front differential oil
 
good info bro!

Chaoul1 12-02-2009 07:48 PM

Re: IMPORTANT: Changing front differential oil
 
Thanks for the info! I'm going to save this one. DO you think this would be the same for the rear differential?

DJ BoNiOmArIo 12-02-2009 07:48 PM

Re: IMPORTANT: Changing front differential oil
 
sucks you had to learn it that way but great write up thank you for the info

RedRocker 12-02-2009 09:57 PM

Re: IMPORTANT: Changing front differential oil
 
Quote:

Originally Posted by Chaoul1 (Post 110346)
Thanks for the info! I'm going to save this one. DO you think this would be the same for the rear differential?

When I had my ZJ I'd just pump the oil into the diffs until it oozed out of the fill hole, never had any problems.

I have a feeling that the factory is trying to shave a few dimes from each diff they fill by inserting the bare minimum amount of expensive fluid, I bet that sometimes they underfill. Unfortunately the engineers didn't take this into account when designing the diff.

jeepfan30 12-06-2009 11:12 AM

Re: IMPORTANT: Changing front differential oil
 
Changed both differentials and transfer case today. After TRZ scared the sh*t out of me with the underfilled front diff (and I lost one myself to locked up pinion earlier) I filled all holes till they ran over. Then with the front one I dumped some more fluid down the front diff ventilation hose. It went in slow, but I feel better now having a little extra fluid.

B.P.O.D 12-07-2009 01:30 PM

Re: IMPORTANT: Changing front differential oil
 
great info!

TimmyB 12-14-2009 07:26 PM

Re: IMPORTANT: Changing front differential oil
 
Odd they would ship an axle already filled with oil. Means the dealer tech is a moron for not checking the oil level after the install though. Just because the packing slip says it comes already oiled, wouldnt you check it to make sure??

dreamer1213 12-14-2009 07:50 PM

Re: IMPORTANT: Changing front differential oil
 
Thats what you're suppose to do...pump oil into it until it starts oozing out of the fill hole. That's the proper level to run most diffs. Some specify a level, like between 1/8-1/4 below the fill hole, but its rare.

Overfilling isn't good either. If you overfill, it'll come right back out that vent tube, or where ever else it can find a spot.

TimmyB 12-14-2009 08:10 PM

Re: IMPORTANT: Changing front differential oil
 
Fill,,,

RedRocker 12-14-2009 10:27 PM

Re: IMPORTANT: Changing front differential oil
 
Quote:

Originally Posted by TimmyB (Post 116770)
Odd they would ship an axle already filled with oil. Means the dealer tech is a moron for not checking the oil level after the install though. Just because the packing slip says it comes already oiled, wouldnt you check it to make sure??

He checked the oil. It met spec. The question is - is the spec wrong especially on a lifted WK, or was the lube path (to the rear bearing) improperly machined.

mosier 02-06-2012 06:56 PM

Re: IMPORTANT: Changing front differential oil
 
Sorry to "resurrect" this from the dead, but I am looking for feedback since this was roughly three years ago. Has anything changed? Is it "common knowledge" now to over fill the front diff when doing the Superlift? What about aeration due to overfilling? Superlift has a seperate part number for the 2008-2010 WK, so is there something different in the lift that would address this issue? Looking for as much info as possiable as the last thing I want to do is blow big bucks on a lift just to screw up my WK. I went through all this hassle with my '01 Sahara and my '99 XJ. Not going through that money/aggrevation again. I really like the "look" of the Superlift, I guess maybe I am asking to much form the aftermarket in demanding perfection for something as nice as the WK. Any feedback on this is appreciated:thumbsup:


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