I have a brand new redhead steering box on my 79 bronco. The other day I went and hauled a 65 chevy truck home on my trailer and noticed that at idle it did not want to steer. If I revved it up a little it steered like it should. Is this the pump going out?? It is not making any noise and is full of fluid. The only other thing I did was pull the truck out of its resting place and had it in 4x4 . The bronco spun in 4x4 a few times but cant see how this would have anything to do with the power steering pump going out. Always before I could turn my tires lock to lock idling on pavement.. If this is the pump has anyone rebuilt one before?