GM Service Manual Online
For 1990-2009 cars only

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

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

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

Engine Oil and Filter Change

For the engine oil and filter changing procedure, refer to Engine Oil and Filter Change in Engine Mechanical.

For information on the correct engine oil quality and viscosity, refer to the following:

Engine Oil Quality


Object Number: 65536  Size: MH

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.

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 (thickness) has an effect on the fuel economy and the cold-weather operation (starting and oil flow). Lower viscosity engine oils can provide better fuel economy and cold-weather performance. However, higher temperature weather condition require higher viscosity engine oils for satisfactory lubrication. When the temperature is consistently above 0°F (-18°C), SAE 10W-30 can be used. 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 transmission shift linkage. Lubricate the park brake guides, the underbody contact points and the 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.
    • 2WD Extended Cab w/Service Only Prop Shaft installed: Lubricate CV type U-joints ball and seats.

Object Number: 869259  Size: SH

Important: Wipe off all dirt from the grease fitting before lubricating the joint. Ball joints should not be lubricated unless the temperature of the ball joints is 10°F (-12°C) or higher. During cold weather, allow the ball joint 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 andy 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: 369702  Size: SH
(1)Lubrication Fittings

Lubricate the steering linkage, the upper 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 Tire Diagnosis - Waddle Complaint in Tires and Wheels..

Accessory Drive Belt Inspection

Inspect the accessory drive belts for the following:

    • Cracks
    • Fraying
    • Wear
    • Proper tension

Replace as needed. (Belts can have many small cracks in individual ribs without affecting the performance.) Refer to Drive Belt Replacement or Drive Belt Replacement in Engine Mechanical.

Automatic Transmission

Change both the fluid and the filter according to the maintenance schedule intervals. For maintenance schedule information, refer to Maintenance Schedule .

For the fluid and filter changing procedure, refer to Automatic Transmission Fluid and Filter Replacement 4L60-E in Automatic Transmission or Automatic Transmission Fluid and Filter Replacement 4L80-E in Automatic Transmission.

Spark Plug Replacement

Replace the spark plugs according to the maintenance schedule intervals with the correct type. For maintenance schedule information, refer to Maintenance Schedule .

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

For the spark plug replacement procedure, Refer to Spark Plug Replacement in Engine Electrical.

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 Harness Replacement in Engine Electrical.

Air Cleaner Filter Replacement

Replace the air cleaner filter according to the maintenance schedule intervals with the correct type. For maintenance schedule information Refer to Maintenance Schedule .

For information on the correct type of air cleaner filter, refer to Maintenance Items .

For the air cleaner filter replacement procedure. Refer to Air Cleaner Element Replacement or Air Cleaner Element Replacement in Engine Controls.

Fuel Tanks, Cap and Lines Inspection

Inspect the following components for damage or leaks:

    • The fuel tanks
    • The cap
    • The lines
    • The fuel rails
    • The injection assemblies

Inspect the fuel cap gasket for an even filler neck imprint and any damage. Replace parts as needed. Periodic replacement of the fuel filter is not required. For fuel system diagnosis information Refer to Fuel System Diagnosis or Fuel System Diagnosis in Engine Controls.