first thing I would do is visually inspect everything. Make sure you dont have any broken axles or driveshafts.

Then make sure you're taking it out of low properly. Make sure you're in Neutral and if you can, try rolling slowly in neutral (via a hill or something) while you take it out of Lo.

If its coming out of Lo properly, try the other gears of the trans manually, reverse too (rule out a trans issue).

If that doesn't work, drain the tcase fluid and inspect.... then fill with fresh fluid and try again.