1997 GMC Sonoma Owner's Manual - Page 369

Drive Axle Service Check readfront axle fluid level and add as needed. Check constant velocity joints and axle seals for leaking. 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.Also inspect drum brake linings for wear and cracks. Inspect other brake parts, including drums, wheel cylinders, calipers,parking brake, etc. Check parking brake adjustment. You may need to have your brakes inspected more often if your driving habits or conditionsresult in frequent braking. Transfer Case (Four-wheel Drive) Inspection Every 12 months or at oil change intervals, check front axle and transfer caseand add lubricant when necessary. Check vent hose at transfer case for kinks and proper installation. More frequent lubrication may be required on off-road use. 7-59