Can you rotate the front driveshaft with the wheels off the ground? If not, there may be a differential problem. To eliminate the possibility of the transfer case, match-mark the position of the front driveshaft at the flanges and remove the shaft. If the transfer case drive yoke will rotate, the transfer case is not likely at fault.
The LH half-shaft can also be removed/separated at the drive flange to help isolate the problem, but it might be just as easy to remove the front differential cover and inspect the assembly. At the very least, you can get some fresh gear oil in it. However, if the oil drains out with metal particles in it, things could be more complicated.
https://www.youtube.com/watch?v=zJ1mcAfMfm0