1990 Cherokee, front differential problem

[m2g4b]

My Grandpa's Jeep is making a BAD noise in the front end...he thinks it is somthing to do with the transfer case. I think what he is wanting to know is how to "unhook" the front differential to pin point the problem. I guess to make it so the internals are not spinning with the wheels, if this is possible...does anyone know of diagram of the front end on the web or something...any help would be greatly appreciated...he is out of state from me right now on vacation and needs some info...thanks again!!!

[Cam7]

He should be able to jack up the front end of the Jeep and turn the wheels to check for noise. The diff shouldnt be engauged unless the 4Wd is activated. If nothing else un hook the front drive shaft. The noise could be from the differential bearings, a bad wheel bearing hub assembly or transfer case. Jack it up and have a good inspection move the wheels and listen for noise. If Nothing Jack up all 4 wheels with Jack Stands and start the Jeep and put in drive if no noise engauge the 4wd and check, should be able to find where it is comming from.