GM Service Manual Online
For 1990-2009 cars only

For time and/or mileage intervals of scheduled maintenance items, refer to Scheduled Maintenance .

The following text and illustrations describe the details of the required scheduled maintenance services.

For information on the proper fluids and lubricants, refer to Fluid and Lubricant Recommendations .

Engine Oil and Filter Change

For information on the correct engine oil changing procedure, refer to Engine Oil and Oil Filter Replacement in Engine Mechanical-6.0L.

Gas Engine Oil Quality

Oils of the proper quality for the vehicle can be identified by looking for the STARBURST symbol. The STARBURST symbol indicates that the oil has been certified by the American Petroleum Institute (API), and is preferred for use in gasoline engines.


Object Number: 65536  Size: MH

Engine Oil Viscosity

The recommended oil viscosity is SAE 5W-30.

Notice: Using oils of any viscosity other than those recommended could result in engine damage. When choosing an oil, consider the range of temperatures the vehicle will be operated in before the next oil change. Then, select the recommended oil viscosity.

Engine oil viscosity, or thickness, has an effect on the fuel economy and on the cold-weather operation, such as starting and oil flow. Lower viscosity engine oils can provide better fuel economy and cold-weather performance. However, higher temperature weather conditions require higher viscosity engine oils for satisfactory lubrication. When the temperature is consistently above -18°C (0°F), use SAE 10W-30. SAE 20W-50 or oils of other viscosity rating or quality designations are NOT recommended for use in any trucks at any time.

Chassis Lubrication

Notice: Do not lubricate the parking brake cables. Lubrication destroys the plastic coating on the cable.

Refer to the illustration for the location of the lubrication points for the chassis. Lubricate the following components:

    • The transmission shift linkage
    • The park brake guides
    • The underbody contact points
    • The underbody linkage

Lubrication Points (4WD)


Object Number: 397004  Size: MF
(1)Transmission
(2)Rear Axle Differential
(3)Transfer Case
(4)Clutch Actuator
(5)Brake Master Cylinder
(6)Oil Filter
(7)Engine
(8)Front Axle Differential
(9)Front Propeller Shaft
(10)Steering Linkage

Lubrication Points (Rear-Wheel Drive)


Object Number: 396999  Size: MF
(1)Propeller Shaft-Slip Joint
(2)Rear Axle Differential
(3)Clutch Actuator
(4)Master Cylinder
(5)Oil Filter
(6)Steering Gear
(7)Engine
(8)Steering Linkage
(9)Transmission

Lubricating Joints that have Grease Fittings

Refer to the illustration for the location of the grease fittings.

Important: Wipe off all dirt from the grease fitting before lubricating the joint. Do not lubricate the ball joints unless the temperature of the ball joints is at least -12°C (10°F). During cold weather, allow the ball joints to warm up as necessary before being lubricated. Use a low-pressure grease gun on all joints in order to prevent seal damage.

Apply grease slowly while watching the grease seal. Apply the grease until the grease is seen bleeding from the seal. If the seal expands but you do not see any grease, do not apply any more grease. Allow time for the grease to bleed from the seal.

Lubrication Fittings-Steering Linkage


Object Number: 369705  Size: SH
(1)Lubrication Fittings

Lubrication Fittings-Ball Joints


Object Number: 1067948  Size: SH
(1)Lubrication Fittings

Lubricate the steering linkage, the upper ball joint, and the lower ball joint.

Tire and Wheel Inspection and Rotation

Inspect the tires for abnormal wear or damage. Rotate the tires in order to equalize the wear and obtain maximum tire life. Refer to Tire Rotation in Tires and Wheels. If irregular or premature wear exists, refer to Tire Diagnosis - Irregular or Premature Wear or to Tire Diagnosis - Waddle Complaint in Tires and Wheels.

Accessory Drive Belt Inspection

Inspect the accessory drive belts for the following conditions:

    • Cracks
    • Fraying
    • Wear
    • Proper tension

Replace the accessory drive belt as needed. Belts can have many small cracks in individual ribs without affecting the performance. Refer to Drive Belt Replacement - Accessory or to Air Conditioning Compressor Belt Replacement in Engine Mechanical- 6.0L.

Automatic Transmission

Change the fluid and the filter according to the maintenance schedule intervals. Refer to Automatic Transmission Fluid and Filter Replacement in Automatic Transmission-4L60-E.

Automatic Transfer Case

Change the transfer case fluid. Refer to Transfer Case Fluid Replacement in Transfer Case BW 4484.

Spark Plug Wire Inspection

Clean the spark plug wires. Inspect the spark plug wires for burns, cracks or other damage. Inspect the wire boot fit at the coils and at the spark plugs. Replace the wires as needed. Refer to Spark Plug Wire Replacement in Engine Controls- 6.0L.

Spark Plug Replacement

Replace the spark plugs according to the maintenance schedule intervals with the correct type. Refer to Spark Plug Replacement in Engine Controls-6.0L.

For information on the correct type of spark plug, refer to Maintenance Items .

Fuel Filter Replacement

Replace the fuel filter according to the maintenance schedule intervals with the correct type.

For correct procedure refer to Fuel Tank Replacement in Engine Controls-6.0L.

Drive Axle Service

Change the axle fluid according to the maintenance schedule intervals.

For axle capacities refer to Approximate Fluid Capacities .

For the procedure to check the fluid level of the front drive axle refer to Front Axle Lubricant Level Inspection in Front Drive Axle.

For the procedure to check the fluid level of the front drive axle refer to Rear Axle Lubricant Level Inspection in Rear Drive Axle.

Cooling System Service

Drain, flush and refill the cooling system with new coolant. Refer to Cooling System Draining and Filling in Engine Cooling.