So for the past couple months I've noticed a slight grinding noise from the front end of my truck and I couldn't tell if it was from the hubs or the front differential. When I would Engage The 4 wheel drive automatic the noise would go away but as soon as I switched it back into 2 high it would come back. Now that there's a little bit of snow on the ground here in Michigan I decided to see if the four wheel drive what actually work. So I Engage The 4 wheel automatic on a slight incline out on the street and my rear tires will spin but I don't move anywhere there's a terrible grinding noise coming from it sounds like either the differential or the right hub. I also tried 4hi and 4lo with the same results the front end just grinding and the truck barely moving but then as soon as I put it in 2 high again I could actually move up the street. Anyways I've never had a truck without manual locking hubs and I've also never had a front-end grind like this before. So before I dive into fixing it I don't want to waste any time and spend money that I don't need to spend.

 

The difference between 2 and 4 WD begins at th transfer case bolted to the back of the transmission. It would be a good place to start to confirm it is going all the way into 4WD. There is an electric motor that makes the switch from 2 to 4 and it might be a good idea to check if that motor is working correctly.

 

It ended up being the four wheel drive passenger side hub assembly and solenoid actuator.