I have a 2000 Cherokee. It has a horrible grinding/whining noise in 4x4. Quiets down when you get up to speed. Its bad when you hit a bump or accelerate hard. I removed front driveshaft, no change. Fresh transfer case fluid and also diff fluids. I have a np231. Is it fubared? Thanks, Kurt

 

What did you use for the fluid in it first off? If that is correct then you may very well have a more serious problem with the transfer case, not a lot of information to go on. Are you sure the linkage is adjusted correctly where the gears are completely engaged while in 4wd?

 

I used amsoil signature trans fluid. Stuff that came out was black and nasty, a touch low also.
Adjust? Tell me more.

 

I have never drained black fluid from a TC, but i have not had one go bad either.
If you are lucky it is just old fluid and the shift linkage is in need of adjustment.
Otherwise it 'could' be a stretched chain dragging on the case, this will eventually wear a hole in the case.
First check the shift-linkage as mentioned. Here is a youtube link;
http://www.jeepforum.com/forum/f9/tr...stment-701221/

 

Now you just need too dump that "Snake Oil" out of your transfer case and use either a factory trans fluid or and good std. trans fluid. That stuff (Amsoil) is all hype about it, besides the TC fluid needs to be changed fairly often also if you off road much of the time.

I may be a little **** about fluids I change everything very often from oil and filters to differentials/transmissions/transfer case. The fluids are cheap compared to what they protect JMHO.

 

Adjusted linkage. 2 hi and 4 low are fine. 4 hi growls when power is applied.

 

Growls in 4Hi only and only while on throttle? hmm, not a bearing, I would guess it has to do with the 'mesh' of that gear selection, the gear teeth.

If it was the chain dragging on the case, then it would drag in 4Lo also.

 

There is nothing wrong with Amsoil ATF for this application. Its not going to trash your transfer case. It is easier to say you used ATF because it avoids the heated passion that some add and people are tired of hearing about. I don't think I've ever read anyone say the transfer case was fixed by draining out Amsoil and putting in Valvoline ATF...

You can see if the chain is a problem by looking in the drain plug and seeing how much sag there is in the chain.

Check the linkage as shown in the You Tube video.

Then be ready to open the case and see what's wrong.

 

Thanks for the info guys. It does growl in 2 wd occasionally when hitting bumps, just noticed that today. Found a few used t cases for reasonable, may tear this one down to rebuild.

As far as amsoil... I run it in my 565 hp Cummins, great gear oil. I also run it in a 1996 Corvette 6 speed, it is the quietest gearbox fluid I have found. Dont use the engine oil, to pricey. Snake oil?? When I find a lube that makes the zf 6 speed shift as smooth, Ill run it.