[Zoomad75]

Might want to check the frame for cracks at the steering box mount. These trucks are known for it. If the steering box is moving off the frame you are not getting consistent steering from it.

Have somebody turn the wheel with it running while you watch if the box moves away from the frame by any amount. If you see movement it could be the mounting bolts being loose or the frame is cracked or both. It will be time for the ORD steering box brace and frame repair kits.