Power Steering Problems...

[72BlckButy]

Okay guys, I recently, within the past 3 or 4 weeks, replaced my powersteering pump due to the bearings starting to whine. Now, my truck doesn't get driven very much, but it does get moved at least once or twice a week. Well, today I decide to drive it into work which is about 15-20 miles away. It drives fine all the way there, and all the way back. I leave it outside the garage to let those headers cool down, and when I go out to pull it in....the powersteering pump is whining again. Does anyone have a possible solution to what is going wrong? Any assistance in this matter is greatly appreciated. I was planning on driving it a much as I can since winter weather is around the corner, but now, it looks like it's going to be sitting. The powersteering pump came from the local Advance Auto Parts, and has a lifetime warranty. And just to add, it did and still does have enough fluid in it, and the lines are not kinked. Thanks!