Hey everyone,
Im new to the site and look forward to alot of good info. on here.
The question i have is with my Front and Rear Diff. Im just soso mech. inclined. But would like to start doing my regular maint. myself. I have a 1997 jeep wrangler TJ, 2.5, 4 cylinder. It is due for Front and rear Fluid change. Are there any threads on here showing the procedure? If not could some one explain in order how to do it. suggested gear oil, tools needed,etc. Things of that nature.
Thanks Again
Mike

Set of wrenches, drain pan, brake cleaner, rags, floor jack and at least 2 jackstands, flat bladed screwdriver, either a tube of black RTV or you can get the gaskets, I prefer gaskets myself, I dislike RTV. I would pickup 6 quarts of gear oil, you can go 90 or 140 weight. I doubt you have a limited slip in the rear but you can eyeball that when you get it open in which case you might want to pick up a bottle of friction modifier, most parts stores carry the Kendall brand in the north east. If you have a LSD it probably has a metal tag on the cover that says so.
Jack up back end put jackstands under FRAME and let the rear end down so it droops. Remove all the bolts EXCEPT one top one, just loosen that one or two.
Start working around the cover and freeing it up, have the drain pan under it, once it frees up the the lube will come out, the reason for leaving the top one or two bolts in loose is to prevent the cover from splashing lube all over the place when it falls off.
Use the brake cleaner and rags to clean out the pumpkin, it should have a magnet in there, look for it and check it for metal filings, clean it.
Clean the cover off, put the new gasket on or RTV bead and reinstall it.
Pop the plug off and refill, refill till it comes out the hole then put the plug back in.
Pretty much the same thing for the front.
Normally all you should have in there is a carrier, ring gear, spiders and pinion gear. Find a picture of a D35 on the net then look at it, if you have more parts in there than that you may have a limited slip rear.
Front is the same way. You can also use synthetic gear oil, that stuff according to the labels already has the friction modifier in it and if you don't have a LSD the friction modifier won't do anything to an open rear.

Richp,
Thanks for the great info., you say its ok to use the friction modifier even if you cant tell the difference between a LSD or not? Dumb question here, do you use the friction modifier in front also?
Thanks Again,
Mike

don't add friction modifier if you don't need it, but you can use synthetic fluid if you like. they sell additives called friction modifier, don't add that if you have a normal differential. i don't spend the money on synthetic fluid cuz if you change it regularly you don't need it, synthetic is at leaset twice as much money, usually more. if you end up wheeling your jeep you're gonna wanna change it bare minimum once a year. or 20 to 30k is what i like. most don't do it for closer to 60k.

if you aren't gonna wheel, and only wanna change it around every 60k, go synthetic. if you wheel it, you're gonna have to change the synthetic, or regular fluid about the same.

why should he need jack stands? you can change the diff fluids without them.

^when you jack it up, and rest the frame on the jack stands, it unloads the suspension, and the differential drops down about 4-6 inches or so, making it much easier to access the top of the cover, and the fill plug

^X2 Thats an advanced trick most experienced driveway wrenchers will know. Its little things such as this that will make certain projects a lot easier.

ok. sorry i didn´t think about that.
i always do that things in my garage on my service lift.

Ok, Ibelieve i have a Dana 35 rear and 30 front, you say i could still have LSD?

Yes, my TJ originally came out of the factory with a Dana 35c rear axle that had a Tracloc LSD. It was an optional extra-cost upgrade for the Dana 35c. Whether or not you have a Tracloc LSD in your rear axle, 99.9% of the gear lubes you'll find in your local auto parts store already have the friction modifier additive required by the Tracloc. That additive is compatible in all axles so most gear lube manufacturers just include it. You'll know for sure if the back of the bottle says something like "Compatible with limited slip differentials".

Lift the rear of your TJ until the tires don´t have contact to the ground.
Then turn abound one tire of the rear axle.
If the other tire turns in the same direction = LSD
If it turns in the other direction = open diff / no LSD

only if someone put one in. most likely you don't.

and nicolas-eric, you suck i have a big garage now, but not tall enough, my next house will have a pole barn and a lift. once you use them you hate working on your back. but luckily i can use my shop anytime i want.

Traclocs were in the back of a lot of TJs right out of the factory as an extra-cost option, mine originally came with one.

My TJ came with a rear D44, but with no TL..

you know what, i was thinking about lockers, and not limited slips. my fault. thanks jerry. they never had lockers until they put them in rubicons right?

You are correct, never a true factory locker until the Rubicon.