One problem related to brake squeaking noise has been reported for the 2001 GMC Sierra. The most recently reported issues are listed below.
All the brakes failed prematurely at 50,000. The brakes were making a squeaking noise, thought it was brake pads, took to dealer, and they said had complete brake failure. Use vehicle for loading and unloading boats in the salt water. Had 6 other GMC vehicles and never had this problem.