Differential Fluid Service Write-Up

Changing the fluid in your Jeep JK Wrangler’s differentials is an important part of routine maintenance. New gear oil will insure your differentials will be well lubricated and function properly. And, unlike previous Jeep Wranglers, it will not be necessary remove the differential cover in order to do this. Granted, I do recommend that you do so anyway from time to time (every other fluid change) as it will give you a chance to inspect your gears and catch any damage or unsual wear. Click on the link below for instructions on how to service your differentials.

MAINTENANCE: Jeep JK Wrangler Differential Fluid Service Write-Up


  1. DO NOT be tempted to fill up your differential with any more gear oil than it needs as it will just end up getting pumped out of the breather tube and make a big stinking mess.

    Lol I did this filling up the front diff =) Funny thing was the stinking left it made was in my friends driveway =)

  2. The Dana 30 is what you will have as a front axle if you have an X or Sahara. A Dana 44 is what you will have as a rear axle on all but a handfull of 2-Door JK’s made in early 2006. Rubicon’s will have Dana 44 front and rear axles and they are a stronger.


  3. Just did this…Great write up. Its sooo easy to do, i will never have anybody do this for me again 🙂


  4. I just did this and I didn’t need as much oil as was listed. I filled until it came out the fill hole but only had about 1qt for the front and about 2 for the rear. Has anyone else noticed this? Just want to make sure that I put enough in there.

    Thanks for the info.


  5. Hey there!
    Just to clarify; I have a X with Rubicon axles. so D44 front and rear.

    I assume they will have the same capacity? just want to be sure i buy enough at the store.

    Thx Craig

  6. if you have an x, you should still have a d30 front and the capacity is about the same. just get the same amount of fluid and fill the same way.

  7. I too was barely able to put 1qt in the front and 2qts in the rear. I have an X by-the-way. Would it be a big problem if there wasnt enough fluid in the diffs? Also, are you supposed to cut the top off the Royal Purple bottle cap? I couldnt figure out any other way to pour it. And do you have to squeeze the hell out of it to pour. …this is why I am not a mechanic. 🙂

  8. I just drained my rear d44 and the oil is black and the magnetic drain plug has about 1/8″ to 1/4″ sludge on it. The history: I had 5.13s in for about 500km and then put my old gear set back in. It’s been 7000km since then and after reading this article I decided to take a look. I’m worried that the gears were installed wrong although they are dead silent. Are my gears OK?

  9. yeah, what you are seeing is totally normal especially after changing gears – even if it’s the orginal set again. after installing gears, they will create new wear patterns and will shed metal.

  10. I just went in for an oil/lube service at the dealership and they informed me that it was time to change out the oil in the diff’s and it was going to run 179 for the front and 169 for the rear. I told him he was crazy and I would do it myself. He said that I could but the oil would cost around $90, about $10 for the aditive and another 15 to 20 for the sealer and gasket. Oh yeah. . . that’s just for one Diff. Do I have to get this stuff from them or can I get it over the counter some where else?

  11. Quick question. . . just changed out the diff oil and everything went well. Very little metal shavings on the rear Diff drain plug (good deal). On the front plug, there was quite a bit more, may be between 1/8″ and 1/4″. The oil looked almost new up front (to be expected, haven’t had it 4wd much compared to 2wd). Is this normal? There is about 21k on the JK and this is the first Diff oil change. Without a dought, it will get done every 15k for now on. Wish I would have found this forum sooner. The dealership will have you thing they are the only way. Spent about $80 verses the almost $375 the dealership wanted. My hat’s off to you and this awesome Forum!!!

  12. Would you recommend using 75w140 in the dana 44 axles if your running new gears with larger tires, example 35’s or 37’s?

    Or is the 75w140 only if your doing lots of towing?

  13. hi trevor, metal shavings in general is normal and not that big of a deal. chunks of metal is a real problem. needless to say, you should be just fine.

    LAHAL, i have run both and you should be fine with either. if you are running 5.13’s, 75w140 would be adviseable.

  14. Just did mine today with Mobil 1 75W-90. Quicker and easier than an engine oil change. Had the same issue as others have written about above. 0nly 1 quart in the front Dana 30 and just under 2 quarts in the rear Dana 44 before the oil spilled out of the fill holes.

    I can’t imagine the amount of oil in the diffs to be absolutely critical. As long as the level is up to fill hole there should be plenty for the gears to splash in.

    Is that aaumption correct?

  15. This is awesome! Dealer told me today it would be $279. do you know of any instructions out there for changing the transfer case fluid for jeep wrangler 08? Thanks!

  16. My manual says to use 80W-90. That is what I used (Valvoline). Is there much difference between 75W-90 and 80W-90?

  17. I did this over the weekend and it was real easy. My experience was similar to others here as far as only 1 quart up front and just over 2 quarts in the rear.

    Question: From the factory, the plugs were apparently installed with teflon tape on the threads. (This was the first change performed on the front. The dealer had to replace the rear diff. gasket. I can’t tell if the dealer used tape on it or if the residue on the plugs was from the factory.) Anyhow, your write-up doesn’t say anything about using teflon tape. Is it OK without it? I haven’t noticed anything leaking in the last couple of days. What do you think? It’s not as easy to check the level in the diff as compared to motor oil or transmission fluid and I would hate for it to get low and lead to a costly repair. Thanks!

  18. I spoke with the dealership and they quoted me $240, but they remove the covers “to make sure all the metal shaving are out”. They said that not all the metal shavings will stick to the drain plug. How detrimental would this be if there are still some shavings and at the bottom of the diff? Thanks in advance!

  19. unless you are doing a routine fluid service after doing a gear install, no, you do not need to pull the cover off to do a thorough fluid change. if after you pull the drain plug you find chunks of metal stuck to it, pull the cover at that time to see what’s going on. but, i seriously doubt that will be the case.

  20. Has anyone put Mobil 1 75-140 in a D44 rear with limited slip? If so, did you have to add the LS additive from Mopar to prevent diff chatter, or was the straight Mobil 1 ok?

    I want to do this my self, but I’m not a mechanic, and don’t know what the LSD needs to be happy. I think my Sahara Unlimited tow package from the factory came with Mopar Syn 75-140 with LS additive added.

  21. Thanks Eddie!
    Dealership wanted $350 to do it but I was able to do it, thanks to your write-up, for $54 & 45 minutes of my time.

  22. good write up I use royal purple in all my diffs,f250,jeep and honda 4whlr no problems, amsol is great but expensive. glad to hear about not using additive

  23. hi, i got two questions. is an aditive needed for rubi axles? only asking cus the dealership said that it was required, but it only would make sense for diffs with limited slip. and the second is the oil capacity with the riddler covers. they look a little bigger than the stock. should i put the normal amount in or a little extra? thanks

  24. you’re dealership is blowing smoke up your rear end or doesn’t know what the hell they are talking about. the additive is only needed for limited slip diffs and just about every synth gear oil i have seen has the additive in it already anyway.

  25. Just wanted to mention that doing the front diff will require a bottle pump. There was no way to get the bottle nozzle over the track bar in order to fill the Diff. Thankfully I had one that I was going to use for the transfer case.

  26. I too just filled my 08 Sahara rear diff with 3inch teraflex lift. It looks like the diff is tilted upward so that the fill hole may me in a lower position than if it had now lift. Because of this I was only able to put in 1.75 qts before it runs out. What should I do? get a pump or am I fine where it is?

  27. so long as the amount of fluid level inside your diff is at least a bit over the bottom of the axle tubes, you should be okay. otherwise, a new diff cover with a higher fill hole is a good solution to this problem as it trying to jack up your rear end to get more in.

  28. I changed my front diff cover for an ARB one on my 2010 rubicon and the dealer ask me to put LSD additive with mopar 75w140 sythetic oil so that’s what did… I read here that it’s not necessary to use the LSD additive but is it just “not necessary” or I have to drain it and refill WITHOUT additive?

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