2009 GMC Sierra 1500 Crew Cab Owner's Manual - Page 554

(e) Make sure the safety belt reminder light and safety belt assemblies are working properly. Look for any other loose or damaged safety belt system parts. If you see anything that might keep a safety belt system from doing its job, have it repaired. Have any torn or frayed safety belts replaced. Also see Checking the Restraint Systems on page 1-91. (f) Lubricate all key lock cylinders, body door hinges, hood latch assembly, secondary latch, pivots, spring anchor, release pawl, tailgate hinges, tailgate linkage, tailgate handle pivot points, latch bolt, fuel door hinge, locks, and folding seat hardware. More frequent lubrication may be required when exposed to a corrosive environment. Applying silicone grease on weatherstrips with a clean cloth will make them last longer, seal better, and not stick or squeak. (g) Check vent hose at transfer case for kinks and proper installation. Check to be sure vent hose is unobstructed, clear, and free of debris. During any maintenance, if a power washer is used to clean mud and dirt from the underbody, care should be taken to not directly spray the transfer case output seals. High pressure water can overcome the seals and contaminate the transfer case fluid. Contaminated fluid will decrease the life of the transfer case and should be replaced. (h) Change automatic transmission fluid and filter if the vehicle Gross Vehicle Weight Rating (GVWR) is over 8600 lbs or if the vehicle is mainly driven under one or more of these conditions: − In heavy city traffic where the outside temperature regularly reaches 90°F (32°C) or higher. − In hilly or mountainous terrain. − When doing frequent trailer towing. − Uses such as found in taxi, police or delivery service. (i) Drain, flush, and refill cooling system. This service can be complex; you should have your dealer/retailer perform this service. See Engine Coolant on page 5-32 for what to use. Inspect hoses. Clean radiator, condenser, pressure cap, and filler neck. Pressure test the cooling system and pressure cap. (j) A fluid loss in any vehicle system could indicate a problem. Have the system inspected and repaired and the fluid level checked. Add fluid if needed. (k) Inspect system. Check all fuel and vapor lines and hoses for proper hook-up, routing, and condition. Check that the purge valve, if the vehicle has one, works properly. Replace as needed. 6-10