Bizzare Jeep behavior- Wheel locking up at low speed?

I'm working on an '88 Cherokee 4wd A/T. Replaced the CPS, got it running, woo hooo. As I'm driving it around the block in circles to see how it feels, things get weird. I'm tightly turning left, maybe at 5mph, and I guess one wheel starts to lock up, and the vehicle goes nuts (I don't really know how to explain it better than that). Once it struggles back to the house, I take it out again, do a bunch of circles, and I can't get it to happen again. I don't think I was applying the brakes when it happened, maybe lightly, and probably not on the throttle at all. I don't know if it was the front or the rear. The rear diff leaks, I have not checked the fluid level yet. I looked at all the brakes, and they look ok.

One thing that may be relevant- Normally, manipulating the 4wd selector does nothing, but tonight I got it to turn the 4h lamp on. Even after I put it back into 2wd, the light stayed on for a while, while this weirdness happened, then after awhile, the light went off.

I know nothing about 4wd, this is my first, so I don't have a clue what this is.

Thanks

Sounds like it was in 4wd while you did the first set of circles, and came out of 4wd before you did the 2nd set.

Jeeps sometimes stay in 4wd for a little bit after shifting to 2wd. Next time try driving in a straight line for a bit, and applying and letting off the throttle - usually creating a little slack in the drivetrain will help it shift out.

Thanks for the reply. What could be the likely causes of the 4wd drive only coming on sometimes (rarely)? I've read something here about vacuum lines creating issues. The lever is kind of hard to move.

Or, is there a technique of getting it to engage 4wd as there is one to get it out of 4wd?

There are a couple considerations...first, if it wasn't put in 4wd often, the transfer case (tc) could be stiff. It probably needs a fluid change also.

Also, the tc might not be aligned properly, especially if it's been in an accident, or if it's lifted.

I'd suggest finding a dirt/gravel road, and driving down it, shifting back and forth from 4wd to 2wd...make sure it goes back to 2wd each time. After that, then do a fluid change and see how it does.

If the vacuum hoses are leaking, then that would also cause the problem; they're easily traced and replaced....take a good look at them as to general condition.