One problem related to power steering pump has been reported for the 1999 GMC Sierra. The most recently reported issues are listed below.
Truck was extremely hard to steer the evening of 12/03/2012. There was a grinding type noise when turns were attempted. Took vehicle to a shop for a power steering pump replacement. The shop change the pump and the solid metal power steering hose. It turned out that the hose was the cause of the problem. The repair went fine and I picked up the truck and drove it for approximately 3 months. It seems the replacement solid metal power steering hose broke in the same place, where it screws into the pump. It is now may 2013, and the second replacement power steering hose has broken again. I willtake it to the shop Monday, may 21, 2013. I am hoping this hose will last. What could be causing this problem?.