You say linkage is moving as it should, do you mean all the way to the transmission? If linkage at trans is good and operating, I wonder if you could put a pair of vise-grips on the driveshaft for the front axle where it originates at the trans and try to turn it and see what happens. You may need to jack up buggy.
This may tell you if a spline is stripped or damage in the front differential, etc.
(Might want to try this first)
You might try jacking up buggy and try running in low with and without 4WD engaged to see if drivetrain is trying to turn the front axle driveshaft.
Hope this helps! Work safe and use jackstands. (Sorry but we have no idea of your mechanical ability and don't want anyone to get hurt.)
Jeff