2000 k2500 classic power steering problems

[Dougis777]

I bought a 2000 k2500 last year. When I bouht it you could spin the wheel with a finger and the wheel would spin all the way with no resistance. I put a new power steering pump on few months later then it got better for a bit. Then it got to the point it wouldn't steer at low speeds or stop unless you were hanging on the wheel. Called the dealer they said change gear box. That brings me to today put the new gear box on and now I can hardly turn the wheel at all moving or stopped. Is it possible to have the pump be bad again? I jacked it up and turned the wheel a bunch to bleed the air out. Turns good when jacked up just not when tires are on the ground any help would be great I'm at a loss now about ready to take it to dealer