Explanation of Scheduled Services. GMC Truck GMC P42 Commercial Chassis 1999

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 1999 🢒 GMC P42 Commercial Chassis 🢒 General Information 🢒 Maintenance and Lubrication 🢒 Explanation of Scheduled Services

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:

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 for Diesel engines is SAE 15W-40.

The recommended oil viscosity for Gasoline engines 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 in Gasoline engines only. SAE 20W-50 or oils of other viscosity rating or quality designations are NOT recommended for use in any GMC Truck vehicles 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 transmission shift linkage. Lubricate the park brake guides, underbody contact points and linkage.

Lubrication Points (Rear-Wheel Drive)


(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)	Wheel Bearings
(10)	Air Cleaner
(11)	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. Ball joints should not be lubricated unless their temperature is 10°F (-12°C) or higher. During cold weather, the ball joint should be allowed to warm up as necessary before being lubricated. Use a low-pressure grease gun on all joints to prevent seal damage.

Apply grease slowly while watching the grease seal. Apply grease until grease is seen bleeding from the seal. If the seal expands but no grease is seen, do not apply any more grease and allow time for the grease to bleed from the seal.

Lubrication Fittings (Driver Side)


(1)	Lubrication Fittings

Lubrication Fittings (Passenger Side)


(1)	Lubrication Fittings

Lubricate the steering linkage, the upper and lower ball joint, and the wheel bearing. Refer to Wheel Bearing Adjustment in Front Suspension.

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

Tire and Wheel Inspection and Rotation

Check the tires for abnormal wear for damage. Rotate the tires to equalize the wear and obtain maximum tire life. If irregular or premature wear exists, refer to Abnormal or Excessive Tire Wear in Suspension General Diagnosis.

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).

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 Transmission Fluid/Filter Changing 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 and inspect for burns, cracks or other damage. Check the wire boot fit at the coils and at the spark plugs. Replace wires as needed. Refer to Spark Plug Wire Harness 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 .

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 in Engine Controls.