1500 4wd suburban 01 bad steering

I replaced the steering pump on the this suburban but it did not fix the problem. The problem is that when the engine rpms are low I lose power steering when turning to the right only…what should I do next??

Time to replace the steering box/rack. It is the only other component left.

Did you follow these bleeding procedures?: http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c152800a6c8e