For those of you interested about motor oil in our 4.0

Otto · **Posted:** Wed Mar 05, 2008 12:13 am

Ive been lurking around the ROF (rubicon owners forum) a lot lately and recently have been engaging myself in a lot of reading about fluids for the rubicon

note that these fluids are for the rubicon, i have no clue what to use in the 30/35's that are on the regular tjs, or in the 231 tcase

heres what i've found:
don't buy based off of brands, you have to read the labels on the oils youre buying, make sure they meet certain specs...

engine:
SAE 10W-30
specs to look for are ACEA A1, or A3 (ACEA A3/B3-04)
6 qts.
as far as a filter i've found the napa gold 1515, but theres tons out there that will work

differentials:
SAE 75W-140
spec SAE J2360
front takes 40 oz.
rear takes 60 oz.

6 speed transmission (NSG370):
MS-9224 compliant oils, theres only a few of these (you can put w/e else you want in there but it wont uphold the warranty)
4.2 pints

Auto trans (42RLE):
ATF+4
8 pints

241 tcase
ATF+4 (you can actually use anything you want, chysler states atf+4 because its what they use in the auto trans and power steering)
4.2 pints

this is all based on research ive done on ROF, so dont ask me any overly complicated questions if you have them, i just thought it would be useful to those over here to have the info in an easy to access place. I didn't look up the 5 speed (nv3500) fluid, but im sure it wouldnt be hard to find.

And to give a real life example, I am changing the motor oil in my 06 rubicon in the next few days to synthetic. The best oil I could find for it was the Mobil 1 High Mileage 10W-30 oil (my jeep has just under 12k miles on the OD, but its a non issue that im putting in oil for high mileage vehicles, it meets the specs). If I ever get around to changing out the diff fluids, the walmart brand Supertech actually makes all sorts of oils that meet the specs for the jeep. A lot of the big names out there dont meet oil specs like redline, amsoil etc. This doesnt mean those oils are bad or wont work in the jeep, its just that they wont meet the manufacturer stated specs, but for all I know those big brand name oils might work better in some cases or worse in others, I dont have any experience to base it from.

Just passing along some info for the people who hang around on this forum. Ill probably post an update after I get some miles on the jeep with the synth in it. Right now it has a hard time with cold starts (temps drop well below zero here at night) and i get lifter ticks all the time and hard starts on occassion, so i hope there is some noticeable difference at least with lifter tick being minimized and starts being easier. And for reference, this is my second car, the liberty being the first, of which I put about 18k on, ive put around 3k on the rubicon so far, so my experience with these things is relatively low.

Hope someone finds this info useful! And another note, tons of people use oils that dont meet these specs and are perfectly satisfied with their results too, but if you're anal about things like I am than you'll probably appreciate finding all this right here.

chefdab · **Posted:** Wed Mar 05, 2008 1:20 am

Well the 4.0 engine is the same for all year TJs. And the transmissions including the 42rle are all the same for all TJs built in model year 2003 or newer. The spec for the NP231 is also to use ATF+4. When I replaced my diff covers, my D44 rear differential actually called for 60 oz. of fluid plus 4 oz. of friction modifier (I have trac-loc) for a total of 64 oz. The D30 in the front I believe was two and a half pints which would be 40 oz.

Otto · **Posted:** Wed Mar 05, 2008 1:34 am

the lsd in the rubicon doesnt need friction modifier, but its included in most of the synthetic lubricants youll find for it, and if you really want to add it its fine to do it, just not totally necessary

For those of you interested about motor oil in our 4.0

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