Im looking at changing the fluids in my rear ends and Tcase. What fluids should I use? I have D30/D35 and np231 Tcase. I am putting a locker in the D30 and the D35 has limited slip. Granted I am swapping in an 8.25 out of a 98 in a few weeks so not even sure if I should bother with the D35. What fluids and how much of each should I get?

 

The t-case uses ATF. The axles use 80W90 dino or 75W90 syn. Some gear oils already contain a LSD additive; if not, add the little tube of additive.

The 'case takes 1 qt. Hopefully someone else will chime in with the capacity of the axles.

 

I will be doing mine soon but was under the impression that the TC could use a light motor oil. Maybe 5w20? If not what spec of ATF?

 

Use Redline MT-90 in the Xfercase and never look back

 

Kool and would syn. be better with the locker being put in? Also do I need a gasket or some type of rtv to reseal the difs?

 

I would only use ATF - it's proven. Either Dex/Merc or ATF+4 will work fine. I use a syn D/M.

 

I like syn, but either should work fine. The choice of whether to use a gasket or sealant is personal preference. "The Right Stuff" works very well...it's not cheap, but I've never had it leak.

 

I just did mine and used black rtv. Followed directions on the package and have had no leaks so far (2 weeks). I also put a bit of RTV on the stupid rubber diff plug. Maybe not needed but I don't trust that thing - prefer the front screw much better.

 

New plug for $2 usually fixes the problem.

 

Yes - I have a few in the toolbox now. Still, I expected threads and was surprised by the design. Maybe I just need a year or two to learn to trust it lol

 

Both of mine have screws in them

 

Your D35 has a screw-in plug? O.o Pics?

Once you get wheeling with a locker, 75w140 in the rear will be your friend. I recommend synthetics in both diffs if it's your daily driver unless you sink them. Any time you risk water in there you need to change the oil - obviously that gets expensive in a hurry with synthetics.

NP231 runs great on a synthetic ATF of any brand. 5W30 is the motor oil they like: It has been tested by Rockland Standard Gear with better results than ATFs.

As for capacity I recall all of them being just over 1qt. There's a sticky on here somewhere with the numbers

Don't use heavy gear oil in the transfer case (certainly not specialized stuff like MT90)

 

Yep it screws in

 

If you go to Amsoil.com
Select your vehicle and year and they will tell you exactly what you need and how much of it is required.
You don't have to buy their stuff but Ive been using Amsoil for 23 years and 513 000km on same jeep without any problems so far..

 

Nice thanks for the heads up