If the fluid is burning up then there must be excess heat in the pump. I figure it must be friction from the belt. (or a bearing but not on multiple pumps) Maybe the belt is the wrong size and is pulling too hard on the pulley creating friction.
How did your steering feel prior to your finding out it was the pump. I went mild wheeeling last weekend and had to do a tight turnaround on a trail which meant a lot of lock to lock turning. Once I got turned around the steering was very stiff. Meaning, I'd turn with more force and the the truck wouldn't react immediately. Now that I'm outta the hills it just feels different. It takes more force to turn the wheel.
Let me know