I just realized with some help from the stealership, that my diff fluid had not been changed on my 2008 jeep. I'm at 30k miles, mostly highway driving with some very mild offroading. Can't remember submerging my differentials, but I am partial to hitting any puddles of water.

The dealership wanted 450 to do my diffs and transfer case, leading me back to the forum for a write up on how to do it myself. Everything went smoothly but had a few questions.

My front diff took just under one quart. And the back took about two. I thought the front would take more than one, but it started oozing before I finished the first. Does that sound right?

The bigger concern is that both diffs had a milky hue to the oil. I'm aware this is caused by water making it into the diffs, but I am not sure of a situation when that would've happen. Could the milky color be coming from the age of the oil? Or is it typical for a small amount of water to make it in? The fluid was mostly black, but just a little cloudy causing my concern.

If water has been in my diff, should I be concerned about another issue arising? Or will simply changing the oil fix the water issue.

Thanks for the help!

 

from what I've heard, 1 quart in front is normal, 2 in rear. Water makes it into the diffs through breather tubes, mainly when hitting deep puddles, you can extend your breather tubes if you do that frequently. You should change it whenever you think you may have water in the oil.

 

Since you now know how to do it and can see how easy it is, you may want to go 1000 miles or so and change it again since it looks like you may have had water in there. Sort of like a double rinse with oil to make sure the water is gone. 1qt in front and 2 in rear is normal.

 

not a bad idea.

If OP hadn't already refilled it it would have been a good time to pull off the covers and spray it down with a can of brake cleaner. Then let it dry out really well before RTV/replace cover.

 

It's just another part of regular maintenance. Diff fluid goes all kinds of crazy colors over time, I remember when I bought my old pickup truck and decided to change all the fluids....the rear end diff fluid was a milky purply blackish swirly mess. Considering how easy it is, you should change your diff fluids at least every 30,000...or more depending how often you're going through water. I changed the fluid in my 2009 at 30k and it was super black, probably due to the cheap LSD clutches wearing. Why Jeep didn't put Truetracs in these things is beyond me

 

Thanks guys, I'll probably change it again in a couple months. Preciate the quick responses.

Next up... Transfer case...

 

Remember how hot differentials run. When they cool they will draw in water through condensation. Or just raise your diff breathers up higher. Black oil is normal with the age of yours. Burnt fluid and clutch material will add to that. Cheers.

 

Just switched my 2011 diff fluid out today. Jeep has 27k on it and the fluid was FN black as midnight in a one horse town. There were some serious gear chunks in there as well. What is acceptable for wear and tear? I kept the pieces and they're not tiny. If I get enough feed back I will talk with the dealer. I can't believe how many pices and the size that came out. The Ring and Pinion looked good upon inspection. Its as the gears up in the carrier that showed the wear and tear. Any suggestions?

 

My magnet had what can be described as magnetic black sludge on it. Only had 4500 miles. From what I know the magnetic sludge is normal. Actual chunks are not. Hopefully you saved them and can show them to the dealer.

 

Yes, I saved them and will be taking them in this week sometime. It will be interesting to see what they say. I'll take a pic and upload them ASAP.