OK, just to test, I drove around all day in 4A. In town up to 25mph, left turns, right turns, with no noise. In a Lowes parking lot, made sharp left and right turns at about 15mph and no noise. All surfaces were hot and dry.

Also while in the parking lot, shifted into 4H made sharp left and right turns at less than 10mph, the noise it made sounded like the front wheels were grinding. This, I would guess, is because there was no give(slippage) while in 4wd. Shifted to 4A, noise gone. Shifted to 2H noise was gone.

Could you have an issue with your traction control system that is not allowing the 4A to operate as designed?