System: fuel; fuel tank assembly.vehicle description: one-ton cab chassis models sold to u-haul and equipped with aftermarket 36 gallon fuel tanks.note: if the vehicle IS presented to an authorized dealer on an agreed upon service date and the remedy IS not provided free of charge within a reasonable time or the remedy does not correct the defect, please contact GMC at 1-810-456-4547. Also, contact the national highway traffic safety administration's auto safety hotline at 1-800-424-9393.