I have a 1990 Cherokee 4x4 with the 4.0, automatic. My son borrowed car and shifted in four wheel drive. He shifted back to 2 wheel drive afterwards. Now when the vehicle is being driven and you are turning the vehicle grinds really bad and jams up and doesn't go until you straighten the steering wheel.

Checked the u-joints and differential but seem ok. When on a lift and you turn it seems ok, but when on the ground it has the problem.

What could it be?

 

Almost sounds like its stuck in 4wd.

How often is 4wd used?

 

The disco axle may still be engaged.

 

prolly still engaged go in reverse slow for a sec and pop it in drive only takes a LITTLE speed

 

That won't make a difference. I've permanently locked my disco axle engaged, never have an issue.

 

You and every Jeep newer than 1991!

X2 that the transfer case may be sending power still. If you get it up on jack stands. Check that the front wheels arent turning in drive, your shifter linkage may be out of whack.

How did you check the U joints?