how hot does your np231 get while highway driving in 2wd??

i just got back from driving 2200 miles from Michigan to California, and something I noticed along the way is that my transfer case was leaking from the slipyoke, turns out the seal is split a little, no big deal.

But something I noticed from checking the fluid level every couple hundred miles (and never letting it get below full) if that the transfer case gets VERY HOT! I can't hold my hand to it for more than a half second. The rear diff isn't nearly as hot.

It drives normally, no noise. But I'm concerned that I may be losing a bearing or something. This was the first long trip (over 20 miles) for me with this transfer case, and the previous owner had it rebuilt just a couple thousand miles before (then rolled his XJ and parted it out). Perhaps the rebuilder screwed something up? Or maybe it's just supposed to be this hot?

I´ve had mine get pretty hot in 4X, on long runs in 4 wheel drive on snow covered roads and such. You can hear the water dropping on the transfer case and hissing and sputtering.
May be hard to tell if the oil is cooked, if you keep adding oil. A sure tip off of too hot, is the Dexron turning a straw or lite brown color, smells bad also.

I have a NP242, so something might be diffrent. But I've checked my case several times, it gets quite warm, but not as hot as you described. Only time it gets that hot while driving is when I'm in the "full time" mode, or using 4x anytime for that matter.

For what ever it's worth: Having been rebuilt, is there any metal shavings or anything in the bottom of the case? Just an idea, I had a buddys trans go out about 2000 miles after being rebuilt cause the output shaft bearing was no good, and gradually ate itself up and thus the dumping of all the metal slivers in the oil ruined a few other parts. I know a trans is unrelated to the transfer case, but theres allways the off chance that something similar could have happend.

I changed the fluid in my 231 a couple weeks ago. After driving about 20 miles, it was hot enough that I had to let it cool off before I could start working on it.

Mine used to get pretty hot on runs to NJ for family gatherings. One trip I changed to Mobil-1 ATF, cooled that case down nicely but now it lubes the slip yoke area a bit so I need to add an ounce or two every couple of months...

My 2000 (231) got just as hot as you are describing. Even if I was driving around town.

On long cross country trips, mine gets hot enough to the point where I can feel the heat comming up next to the seat and the shift lever is hot to the touch. I wouldn't worry about it.

thanks guys, I guess i'll just leave it be. it never did get hot enough to cook the ATF.