Normal for it not to move in AWD as the system provides power to both axles through a clutch type differential in the transfer case. When you select 4WD it mechanically connects the front and rear drives together and bypasses that differential so you have positive drive to both axles. In AWD you can actually spin one tire if you have poor traction, in 4WD you will spin at least one at each end with open differentials.
I attached the info below from the manual that will give more info on this.
As to driving it in 4WD, yes you can but it isn't the best thing for the transfer case as it will now spin both the rear and front shafts full time.
As you will see the manual below tells you that this should not be done due to the reason I stated above.
but you will want to keep it in 4WD if you park it using just Park, without the parking brake engaged and the front driveshaft out the truck would effectively be in neutral in the transfer case as the lack of the front shaft will let it spin free, just like it doesn't move when you put it in gear, the park pawl won't hold it.
I would suggest getting a replacement front shaft, or rebuild the one you have if the front CV joint failed (common) you can get replacements through many parts stores, same with the rear universal.
Images (Click to enlarge)
Sep 12, 2021 at 2:51 PM
