I hate to say it but in 123k miles I have never changed the f/r differential or xcase fluid. (I have the tranny fluid completely changed every 30k).

I am going to do the tranny myself this time and am thinking of doing the differentials and xcase also.

Is it OK to change the fluids for the first time after all those miles? Am I going to get leaks or cause any other problems?

 

"Is it OK to change the fluids for the first time after all those miles? Am I going to get leaks or cause any other problems?"

1) Sure.

2) Doubtful. Use the correct fluids and be mindful when you reinstall the rear diff cover. Oh, and if your rear is limited slip, use fluid with friction modifier or purchase some when you refill.

 

I did the front and rear diffs today.

The front diff oil was nasty and way over due.

The rear looked great. I was surprised.

Question

The rear 9.75 diff is suppose to only take 5.5 pints. I put in just shy of 3 quarts and the oil is still a 1/4" below the fill plug hole.

Aren't you suppose to fill it up till the oil comes dripping out of the fill plug? Once I realized that I had past 5.5 pints and the oil level was just below the fill plug, I called it good.

When I had the cover off I did scoop out some of the oil at the bottom of the pumpkin so that it would stop dripping. Maybe the 5.5 pints is not the dry fill amount?

What do you guys think......

I'm going to do the xcase tomorrow.

 

if its within 1/4" of that hole id say your fine. put atf in the transfercase.

 

I ended up using royal purple max gear 75-140. I had some in the garage that I was planning on putting in the jeep but never did since I change out the fluids in the jeep diffs all the time (water).

It's a little late now but it seems royal purple has a hit or miss rep.

Anyone using it in the rear diff with no problems?

How many miles should I go before changing it out? I doubt another 123k miles is the smart thing to do

I put mobil synthetic 75-90 in the front.

 

Thanks. I got the ATF ready to go.

 

I've used Royal Purple & Lucas Oil in my transfer cases, transmissions, and differentials without any problems what-so-ever. I don't have a brand preference. I just use what is available locally and at a good price. Try to stick to a quality synthetic or known products like the Royal Purple, Mobil 1, Lucas Oil, Red Line, or Amsoil.

 

Isn't the transfer case and the transmission fluid separated by a plate so the fluid doesn't mix? I just assumed this meant that they used different fluids for some reason. I wouldn't know for sure though since I haven't drained the TC and refilled it before. I need to do that though so I better start looking into it lol

 

They are seperate but use the same fluid.

I changed out the xcase fluid today (and put in a new fuel filter) and it made a huge difference. I was starting to get a loud "clunk" noise when I would engage 4wd. After the fluid change that noise is gone and it engages SMOOTH!!!!!

The fluid was BLACK...... Don't wait like I did to change out your xcase fluid. It is real easy to do, there is no reason to wait.

I also undid the fill plug first and I am happy to report that the seal between the tranny and xcase is NOT leaking.

Only fluid left to change is the tranny and then it is on to the brakes and front end/steering.

 

Yeah, I just finished putting a new transmission and transfer case in today. Just have to fill them both with fluid in the morning and then take her for a test drive.

 

bumps .

 

Is there a point to bumping a thread that is almost two years old?

 

I just bumped it cause it had good info. I figure other people might find it useful and easier to find.

 

I'm new here and read it. Thanks for bumping it.