So what exactly happens when you turn the wheel?
Is the wheel hard to turn?
Does the engine go: Vroom but your road speed doesn’t increase? or (less likely) does the engine not vroom and you still accelerate slowly?
Do the tires chirp or squeal when you turn the wheel sharply and try to go forward?
Does it work all okay when in 2WD?
have the transmissions, differentials, and transfer boxes ever been maintained, by flushing and refilling their liquids, and were they refilled with the fluid recommended in the owner’s manual, or whatever Jiffy-Lube had on hand or whatever premium fluid the sales manager could talk you into?
All important clues.