Power Steering Pump problems of the 2002 GMC C2500

Vehicle is a 2002 GMC hd 2500 pickup truck with a duramax diesel engine, and 5 speed allison transmission while driving on surface streets, the power brakes and steering both went out simultaneously. Stopping required both feet on pedal, and steering was nearly impossible. Problem traced to the "hydroboost" and the power steering pump. Both were replaced along with the high pressure hose. Evidently, the pump failed to yield any boost pressure, which in turn rendered power steeling and brakes inoperative. A very dangerous situation. The tow truck that responded indicated that they have had multiple failures of the same items (87 ot 8 GMC hd trucks) and in blogs with other GMC/chevy diesel owners it appears to be a common defect. There were no noises, or other indicator of pending problems. Contact with the dealer revealed that " I should change the ps fluid every 2 years: (not in the maintenance section of owner manual).