Twice in the past week I have experienced a grinding noise after shifting, electronic shift, from 4H to 2H. This happens maybe once out of every eight or ten shifts to 2H, not all the time. The sound is a metal to metal grinding about once per tire rotation similar to a worn brake pad or a pebble caught in a backing plate. Both times the noise stopped after making a sharp right turn from a stop. I pulled all the wheels and blew out the backing plates, but found nothing. I also checked the driveshaft and CV boots, but can't find any signs of interference. There doesn't appear to be any slop from the ball joints or wheel bearings. A search here didn't turn up anything. Any input?

 

I would say drain the transfer case and refill with Merc 5. Use a suction gun to grab heavy stuff at the bottom. You may find something floating in the chain drive. Good luck!