I recently picked up a 93 xj 4.0 4x4 (because who gets a 2 wheel drive jeep?) and the four low won't stay engaged! I'll put it into four low and my part time light will come on for a second then cuts out but four high works fine? I'm the only one to have taken it off-road of any sort as the previous owner used it as his daily and wasn't exactly the two tracking or mudding type. Anyone have any suggestions?

Check the linkage from the handle to the T-Case, mine was off a little bit and I had the same problem.

Yup check the linkage first for adjustment.

Are you depending on the dash indicator light to tell you if 4L is engaged? If so don't worry about the light the T/C switches fail on a regular basis.
When it's in 4L and the light is off does the steering bind if you make a tight turn on dry pavement?

Regardless of the part time light being on or off, if you put it in 4L and it moves at all, it's in 4L. Otherwise the case would be in Nuetral

Oh yeah I didn't even think about it still movin or not I only tried it going onto a trail but I'll check it out tomorrow. If it in fact is out how would I go about checking the cable? I'm new to jeeps and haven't had it but a few weeks and haven't worked on it much other than the basic repairs

Adjust the shifter linkage.. You can ONLY trust the light IF you know the linkage is correct. Main reason is that the light switch doesn't care if the linkage is even attached.

Ok well I went out and put it into low and I was hard as hell to get it back but I finally got my lever all the way back and had it engage but it made an awful noise while engaging but it went away after I felt it engage. But I went to put it back into 2 high and It was hard as hell to get her back down . Would this be the linkage as well?

More issues! I went and put it into four low and it engaged alright with noise like before but about 30 feet down the trail it slipped out of gear and into neutral. Any ideas? Also when it did that my heater valve shattered.. Don't think it has anything to do with it but I got super lucky somehow when the only parts shop in town had one in stock when i was getting towed home.. That's an embarrassing feeling haha

The light is tripped by a selector switch on the transfer case itself, not the handle. If the linkage were not attached, the light would never trip and the handle would move without resistance.

OP; when the linkage is out of adjustment, it's difficult to get the lever all the way back to 4L. And, if it does engage, it will just barely engage and likely pop out under throttle. Would also explain the grinding.

Search the forums for how to adjust it. Also, have someone wiggle the shift lever back & forth while you crawl under your jeep and check for play/slop in the linkage. You'll see there's a rubber/plastic bushing connecting the linkage, it wears out.