u/KINGKONGHAS-ED

I have an 04 f350 6.0 bone stock 267,000. When im driving in 2wd, 99.99% of the time, it drives perfectly smooth. When I lock the hubs and put it in 4, I can hear some grinding in the front driverside tire. Its pulled me out of the snow just fine, but it doesnt sound great and does make it feels like the tire is loose or wobbly. Of course thats only going like 3mph and 10-20ft. Then unlock the hubs and its back to smooth no noise driving. It is an electronic transfer case. What would cause this? Been working on my cars for 20 years but its my first 4x4 so im just looking for some insight before I tear the front end apart.