2003 GMC Sierra 1500 Pickup Owner's Manual - Page 516

Throttle System Inspection Inspect the throttle system for interference or binding, and for damaged or missing parts. Replace parts as needed. Replace any components that have high effort or excessive wear. Do not lubricate accelerator and cruise control cables. Brake System Inspection Inspect the complete system. inspect brake lines and hoses for proper hook-up, binding, leaks, cracks, chafing, etc. Inspect disc brake pads for wear and rotors for surface condition. Inspect other brake parts, including calipers, parking brake, etc. You may need to have your brakes inspected more often if your driving habits or conditions result in frequent braking. Transfer Case and Front Axle (Four-wheel Drive) Inspection Every 12 months or at engine oil change intervals, check front axle and transfer case and add lubricant when necessary. A fluid loss could indicate a problem; check and have it repaired, if needed. On manual shift transfer case, oil the control lever pivot point. Check vent hose at transfer case for kinks and proper installation. More frequent lubrication may be required on off-road use. 6-17