What type of oil do YOU use on your Jeep.

[JeepN4kc]

I love threads like this because it gives some real world feed back to everyday maintenance stuff.
Since the WK is a dd and I take it wheelin from time to time I like to stick with the good stuff
in hopes I'll squeeze every last mile out of this thing to the bitter end. It just clicked over the 60k mile mark
and I keep with the regular maintenance intervals from the FSM. These are the fluids I use:

Mobil 1 5W-20 full syn and Mobil 1 filter for engine

Mobil 1 syn 75W-140 for f/r diffs

Mopar NV254 for t-case

Mopar for trans

[Tazer15]

Better get some mopar limited slip additive in the diffs I had a wk and used same stuff your using the diffs didnt like it till I added the mopar stuff

[mujeeper]

Maybe I'm crazy, but I've heard that using synthetic when not spec'd may cause leaks. I was researching the oil to use on the o' ladies truck (99 F150) & ran across some f150 sites that have similar discussions. Some said they had issues when using synthetic oils. I bring this up because I was thinkin about trying mobil1 in my 95 yj to see how it runs, but may stick with valvoline.

And for the truck I stick with motorcraft. Recommended by Ford. I think a 10w30, but I'd have to check.

[JeepN4kc]

Better get some mopar limited slip additive in the diffs I had a wk and used same stuff your using the diffs didnt like it till I added the mopar stuff

My WK has quadratracII - no ELSD. The QuadradriveII 4x system had ELSD's and requires the limited slip additive.

[JeepN4kc]

Maybe I'm crazy, but I've heard that using synthetic when not spec'd may cause leaks. I was researching the oil to use on the o' ladies truck (99 F150) & ran across some f150 sites that have similar discussions. Some said they had issues when using synthetic oils. I bring this up because I was thinkin about trying mobil1 in my 95 yj to see how it runs, but may stick with valvoline.

And for the truck I stick with motorcraft. Recommended by Ford. I think a 10w30, but I'd have to check.

I've heard that as well. It usually is in regards to older engines with "looser" tolerances from normal wear and tear and the full syn oils being thinner can pass through easier than conventional.

[Tazer15]

Ahhh you are correct was just taking for granted looks like your doin what id recommend then unless you wanna upgrade your filter Donaldson makes the best out there I use an oversized one on my LJ allows me to run almost another quart of oil great for wheeln alot off camber situations.
Ive heard synthetics can cause leaks if not used from the get go but ive switched all my rigs to synthetic and never had a leak.

[JeepN4kc]

Ahhh you are correct was just taking for granted looks like your doin what id recommend then unless you wanna upgrade your filter Donaldson makes the best out there I use an oversized one on my LJ allows me to run almost another quart of oil great for wheeln alot off camber situations.
Ive heard synthetics can cause leaks if not used from the get go but ive switched all my rigs to synthetic and never had a leak.

That's very interesting. Does it have the same thread count to screw on or does it require an adapter?

[Tazer15]

Its the same on my LJ as for the WK I never got a chance to use a donaldson I used K&N. But you can just use whatever donaldson calls out for your WK doesnt need to be bigger. unless you wheel it alot theres not much use unless you just want to. I cant remember how much room there is for a larger filter in my WK prob not enough but I had a Hemi in mine.I order my LJs Donaldsons several at a time from Skinny Pedal he stocks them.

[Tazer15]

Everyone interested in oils and refuse synthetics should read this zddp zinc etc etc is very very important in our motors.It's not so much about synthetics(1 recommended oil is a reg dyno) it's what's in some of them many many 05/06 4.0 owners are having major issues and although there is debate that oil doesn't help their oiling issue it could help.there's also proof on this page of lifter damage due to using the wrong oil.This is very good reading it's long and will take several days but it's worth it.Remember there's nothing wrong with change or admitting your wrong.:-)
Section 8 is about oil the rest is about the major issues with the mainly 05/06 motors
http://www.jeepforum.com/forum/f9/20.../#post10663471