One problem related to axle assembly has been reported for the 2002 GMC Sierra. The most recently reported issues are listed below.
While driving at 45 mph, the vehicle was violently thrown about and skidded to a stop. Upon inspection of the vehicle it was noted that the front axle vent plug broke and all the oil leaked out and caused the differential to seize. From what the consumer understood there was little or no protection, such a shield or guard, to deflect objects from striking the assembly.