TonyPa

I just bought a 1998 Grand Limited Edition. 5.9/Automatic. 186k on it.

First I must admit. This has more power than I thought it would. Very impressed. I have a stack of records that came with it. This guy truly took great care of it. I live in the rust belt but this thing is clean. Just slight rust at the bottom of the tailgate. No where else.

He had the transmission serviced regularly and everything else. He used a really reputable tranny shop right near me. I see he even added Tranny cooler and new selonoids with the last fluid change. Says on the slip...chrysler trans fluid. I am going to call them and see what that was.

The oil is extremely clean. Although he said its almost time for the oil change. Runs about 40-50 lbs of psi if these factory gauges are accurate at throttle.

Anyhow...sorry for the story. I just am impressed and really like this Jeep. Just bought it three days ago. Drives nice. Little strange compared to my wifes compass.

My question since I probably bored you now....lol

Before I get into buying fun stuff. I looked underneath and see a extremely clean Jeep. But...I would like to change the differential fluids in the rear and the front.

Looks a little crappy...the cover. I want to pop it off clean it up.

What weight diff fluid? And its that AWD I guess? Theres no 2wd on my lever. Just Hi and Lo?

I dont know what weight or if I need some type of additive? I forget what its called.

I wanted to add some photos of my new to me jeep. Didnt know if that was okay or not. And advice is truly appreciated. It was cared for so well. I just feel the need to do this part. I'll sleep better...lol

dave1123

My book calls for 75W-90 in the front axle and 90W in the rear, unless it has the tow package, then 75W-140 synthetic in the rear. I personally use 75W-140 syn in both axles. The Quadra-Trac transfer case takes a special Mopar lubricant.

When I service my differentials I just use blue RTV to seal the covers and they don't leak at all. Just make sure the surfaces are clean and dry. If the rubber plug in the rear diff leaks, it's easily replaced with a new one. Your 5.9 may have the D44a aluminum center housing rear diff. Don't overtighten the bolts because of the aluminum.

Sounds like you found a cherry. Don't abuse it, unless that's what you bought it for! LOL!

R.P.

Congrats on the ZJ & finding a 5.9!!
I bought one a little while ago for my 17 year old daughter for her winter rig
(Her Cabrio is now covered in the garage)
I'm on the hunt for another ZJ for my boy, who got his permit on Tuesday...
Can't wait for the weather to get nice again so she goes back to her convertible & I get the 5.9 back!!

TonyPa

Oh I forgot to mention mine does have the tow package. I guess its 75/140 then. I used that Redline 75/140 synthetic on my other car for posi, has the additive in it I guess. Just said for posi rear diffs.. I guess its good stuff? Unless Wal Mart has one you like??? The Redline is expensive!

Do I add anything to that. I don't know if mine has posi or not?

Is that what I have in my 98 limited a Quadra-Trac transfer case? I'm still learning this truck. Is it hard to change? Maybe I should do that too. I have a Dodge Jeep dealer up the street from me. Hope they know the fluid for the T case. They seem a little stupid there sometimes.

I have the blu rtv on hand. I always use that stuff. I'm not sure what rear I have.

Thanks shes clean. No...i wont be abusing. Just typical driving. I baby my vehicles. Thanks for answering me.

TonyPa

Thanks!! I really like this Jeep. Have to figure out my heated seats. Switches light up on dash but they dont warm up. Not a big deal though. This 5.9 seems healthy. I bet you cant wait to get yours back!!
Heres a few pics...IGNORE the horse head vinyl decals. I have to remove them

dave1123

I LIKE the wheels! They go well with the black. Are the hood vents functional or just decorative? If the former, I'd open them up, shielded from the rain of course.

R.P.

Yes sir...
The heated seat fix is on my short list as well...
Those wheels are pretty cool..not my flavor but that's a really flashy set up...
We still have the OEM 16's on ours..

TonyPa

Thanks guys! He spents some serious money having the wheels powder coated. Their 16 inch. Two tone powder coated. He did a 1 inch lift with some type of spacers. Theres those white shocks with the red boots. Rancho or something? Still getting used to 4wd stuff

I dont know if mine hood vents are functional or not? I guess I can check the hood liner stuff when I open it tomorrow. Should I cut it out? I guess more air the better?

R.P.

DON'T MESS WITH THE LOUVERS! !!!
They are one of the many features that make the 5.9 special. .

Do a quick search, there are MANY threads on this great forum that will educate you on all the special upgrades that the 5.9 has...
Louvers, electric fans, sound bar, different leather, etc etc

TonyPa

Okay...I'll leave those alone. I can't believe how many features this truck has.

I'm pulling it in the garage tomorrow. Just trying to figure out what exact fluid to use in the differentials. And if I need that additive...friction modifier?

I don't want to harm anything with the wrong fluid or additives if it needs or don't need it?

andrewmp6

The friction stuff is if you have a lsd or locker but i don't see any harm using it in a open diff i have before with out any problems.

dave1123

The friction modifier is to make it more slippery so the friction plates in an LSD don't stick together and cause erratic engagement. It won't hurt an open diff to have a little slipperier lube in it! The Synthetic stuff has some in it, but an LSD could use a little more. When you buy the additive alone, it's just like a toothpaste tube full. I doubt your 4wd has an LSD in it unless it was specially ordered with it. It was only an option with the 2wd models.

BTW, that's an NP249 t/case. It requires a special Mopar lubricant and it isn't/wasn't available elsewhere. It has to deal with the heat created by the viscous clutch.

TonyPa

Thanks guys!!! Okay I'll add it just in case then. I thought I could turn the drivers wheel forward, and if the passenger side moved the same direction it was posi. I may be wrong. I think this 1998 model with NO 2wd available threw me off. I pictured AWD in my mind.

I will go to the Jeep dealer and get at T case fluid then. I didn't even look at it yet. Should be just a drain and fill plug on the T case.

I seen the tranny was done about 1 year ago. But it doesn't say T case on the receipt. So i can't be sure. Might as well do it.

Fred/N0AZZ

I don't think you can get a build sheet on your 98 I would still try just to see all that came installed on it, when I did on my 04 WJ I was amazed on what it had that I knew nothing about.


My 04 WJ "Overland Edition." with factory tow pkg., V-8, Up-Country came with a D44 LSD in rear and a D30 LSD in front with 3.73 gears. Yours may have several options that your unaware of still on it. Mine ended up having about every option offered by Jeep that yr.


That is a very nice ZJ you have should be a pleasure to own.

TonyPa

Well you hit the nail on the head. I went to advance auto. He didn't have the rear.

He said I have a Dana44 Rear, and Dana 30 in the front. My son is running to O'Reillys for me right now for the rear. Is this Dana44 a good rear? Sorry still learning mopar.

I bought the diff fluids and the transx friction posi additive. That''s all they had for the additive. 7 ounces. I only bought one tube. I might need it for the front also?

No one had the new rubber plug..ugh...might reuse mine with silicone.