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IcarusLSC 12-08-2012 11:38 PM

Diff fluid mix up, ATF in rear!?
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I have been getting a good chatter/grab in the right rear of my Jeep the past couple weeks coming off the highway and turning (not noticed which way, but left I think?) I've not been driving it much at all, so only been on highway 3-4 times and it did this.

I haven't had time to look at it so dropped it off at a smaller shop I know today and had them take a look at it, and possibly change the diff fluid. We were thinking grabbing p.brake or something inside the axle. Brakes looked pretty good though, so did the diff except for the fluid in the rear one:

They said in the rear it looked like dirty ATF (reddish) that came out! They cleaned it out and put in Mopar 80w90, but no modifier.

Should they have put friction modifier in with the rear Mopar fluid? I do have a limited slip D44 rear, so I'm thinking yes? Think the diff is screwed?

It is quieter already, so I'm hoping whoever had it last screwed up and put in ATF. I hope this hasn't damaged anything bad as I've only put about 3000 kms (~1870 miles) on it since I bought it a few months ago, but not sure when it was changed last.

Should I go get a 4oz bottle and put it in the rear diff? Flush/fill again? Think its screwed up if it was indeed ATF in the rear?


Jeeper4life 12-08-2012 11:41 PM

I would put the friction modifier in, You shouldn't have to drain it again to add it though, it comes in its own bottle/ tube.

2JeepsThatRun 12-08-2012 11:42 PM

I had the same question a while ago. I talked to a mechanic and they use to not add whale oil to the standard diff fluids but now they are adding it so I would say your good but if you want you could probably add some whale oil just to be safe

mn jk jeeper 12-08-2012 11:43 PM

yes you should put in some additive a.s.a.p
amd after a hundred miles or maybe less flush and fill again and repeat as needed till all the atf is out of the diff

jkp 12-09-2012 03:11 PM

I don't believe the Mopar fluid comes with the additive in it, so you need to add it.

30-284 12-09-2012 05:34 PM

If they put synthetic fluid then it usually comes with the friction modifier in it.


doclouie 12-09-2012 06:02 PM

Yes the additive is needed so you should put that in ASAP. I would not worry about draining it again as the shop just did that. This is a good time to go through the whole vehicle and change out all fluids as it seems the PO did not know what he was doing. I always change out all fluids when I buy a used vehicle as you never know if the PO actually did any maintenance or did it properly. Just my 2 cents, but my last Jeep had 249,000 before the wife ran it into an electrical pole and totaled it.

IcarusLSC 12-09-2012 07:25 PM

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I had changed all the fluids but the diffs and transfer case already when I got it. Even bleed the brakes! I just hadn't gotten around to these last ones yet. (Oh I edited as I forgot I've not done the PS fluid yet.)

I'm pretty sure the Mopar 80W90 is dino oil, so I'm picking up some modifier to add to it.

I might pick up some extra fluid and modifier and change it again in a month or so.

doclouie 12-09-2012 10:42 PM

Just pull the front plug to make sure it is gear oil and not some other fluid like the back end.

IcarusLSC 12-09-2012 10:58 PM

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I had them do it with the rear fluid as well :)

C.L. 12-10-2012 06:49 AM

You sure the PO didn't just do service with Royal Purple? That stuff looks like ATF after a month or so.

IcarusLSC 12-10-2012 02:16 PM

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I'm not sure, could have been?

IcarusLSC 12-22-2012 05:03 PM

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Been quiet so far with the 80W90 and modifier in it.
Don't know if the clutches are doing to good I think, the breakaway torque if you only lift one side seems a bit low (by hand, so not with tool, so not very accurate way to tell, lol,) compared to my Ford that had a clutch type LSD. Then again the Ford had 7-8 discs in it compared to the 2 I think in these? I don't think the Jeep ones are easily replaceable like the Fords though either, so guess I'll have to live with it or regear sooner that later, lol... ;)

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