I have a question concerning my 1995 Jeep Grand Cherokee 4WD all time 5.8

As I started out driving my Jeep starting making a clunking noise.  It seemed when it was shifting it did this.  At first I thought it may be tranny.  I pulled over and checked fluid which was fine.  I continued to drive slowly and intermittently the clunking continued.  What I discovered was there was a vibration coming from the SECOND shifter which I never use think it is the transfer case.  It is only used if you want to go from 4 all time to 4 lo to take on beach etc.  I never use it.  It was as if something underneath was hitting upward and trying to knock it out of 4W all time to 4 LO.  I then pulled over and discovered when I put it in Reverse it started making a horrible grinding noise.  I was afraid to drive it.  A state trooper pulled over to assist me.  I made the decision to drive it home in 4 LO at 10 mph because it seemed ok but did not want to go faster.  I made it home safely and took to my mechanic who is excellent. He diagnosed the motor mounts.  I disagreed with him and was not there to see it. I asked him what they had to do with the grinding.  Long story short he said that the motor was hitting the linkage and bent it so he replaced the motor mounts and REPAIRED bent linkage.  He did not replace the linkage which is what I would have asked to do.  I picked up car and drove 15 miles home and heard NOTHING.  Then that evening when I went to grocery store it DID THE SAME EXACT THING!  I suspect it is the linkage need replaced but am at a loss here. He said that he checked the transfer case fluid etc and all other components.  PLEASE HELP!  Jennifer