I have a '95 S10 with 4WD.

I used 4WD for a couple of days on snow covered streets, put maybe 20 miles on it. I briefly switched into 4WD LOW, too, just to see if it worked

I noticed that when I turn sharply and move slowly (like when I'm getting into or out of a parking space) I feel a substantial jerking motion. At first I thought my front wheels weren't pointing in the same direction, but they look fine.

Now I suspect that one back wheel is sliding momentarily as it turns.

I have it in 2WD now and it's still doing it.

Any idea what it is?