went to use my 4wd and it started to make a grinding noise. Help on the noise?

Had a similar issue with 2002 Jeep Liberty. Had several mechanics look at but none could find the problem. It started making loud squealing and clanking noise while driving at low speed. Found the problem to be the short driveshaft coming from the 4x4 transfer case to power the front wheels. The problem was at the connection point for the shaft which apparently was worn out.(Found by grabbing the shaft and wiggling on it) Weird because I used the 4x4 only a few times. I did not use 4x4 very often, so I just removed the shaft and all is well. This was several years ago and the cost to replace the shaft was about +/-$400-500. Hope this gets you in the right direction.