2015 chevy suburban. pulled out of driveway in 2wd, service 4wd light came on. actually when backing up it slowed down and would barely move. drove forward a bit and grinding noise and wheels seemed to lock up. put in 4wd and seemed to be fine. came to stop sign and it happened again. barely made it home. rubbing feel when turning from front end

 

You might change your transfer case and front diff fluid or at least make sure they have fluid in them as a starting point.