power steering issues

04 2500 when sitting still and turning the wheels it turns just a little and then acts as if it does not have power steering. Fluid level is good. Could it be the pump getting weak or is there possible a problem in the steering box?

What sized tires? When i went to 37's I got this. I put a bigger pump on it (AGR's biggest) and that made it almost as good as stock. The nest step would be to put a hydro assist.

I got this after I put on an oe replacement pump after it started leaking. I haven't had time to mess with it yet but I suspect a bad pump, engine rpm increase and still no assist while sitting still.