Yesterday I put my 2015 Ed in 4 low. Everything worked as it should, and was pleased with the torque. Upon switching back to 4 high, it said it was in but had no forward or reverse. 2wd same thing. Switched back to 4 low and everything worked fine. Switched back to 4 high and put it in drive, gave a little pedal and it started grinding, put in neutral. When I put it back in drive it worked fine, switched back to neutral and put it in 2wd. Everything works fine, have not tried 4wd again yet as I need my truck on the road at least a few more days before it can go in.. Any ideas as to what it could be?