For 1990-2009 cars

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 .

### Diesel Engine Oil Quality and Viscosity

Refer to the Caterpillar® Operation and Maintenance Manual.

### Engine Oil and Filter Change

For the 8.1L engine refer to Engine Oil and Oil Filter Replacement in Engine Mechanical - 8.1L.

### Gasoline Engine Oil Quality

The STARBURST symbol indicates that the oil has been certified by the American Petroleum Institute (API). Do not use any oil which does not carry the STARBURST symbol.

### Gasoline Engine Oil Viscosity

Engine oil viscosity - thickness - has an effect on fuel economy and the cold-weather operation - engine 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.

SAE 5W-30 is best for your vehicle. However, use 10W-30 if the outside temperature is higher than 18°C (0°F). Do not use other viscosity oils, such as SAE 20W-50.

Important: If your vehicle is operated in an area where the temperature falls below -29°C (-20°F), consider using a SAE 5W-30 synthetic oil or a SAE 0W-30. Both will provide easier cold starting and better protection for the engine at extremely low temperatures.

### Chassis Lubrication

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.

#### Single Axle Models

(1) | Propshaft Slip Joint
(2) | Parking Brake Clevis Pin (Hydraulic Brakes Only)
(3) | Clutch Release Cross Shaft (If Equipped)
(4) | Master Cylinder (Hydraulic Brakes Only)
(5) | Steering Tie Rod Ends
(6) | Steering Column U-Joints
(7) | Front Wheel Bearings
(8) | Front Steering Knuckles
(9) | Brake Cam Roller Pins at Interface of Pin and Shoe (Air Brakes Only)
(10) | Slack Adjuster (Air Brakes Only)
(11) | Brake Camshaft Brake Caliper Rails (If Equipped)
(12) | Steering Column Slip Joint
(13) | Steering Drag Link Ends
(14) | Pivot Points and Hinges
(15) | Pivot Points and Hinges
(16) | Brake Camshaft Brake Caliper Rails (If Equipped)
(17) | Slack Adjuster (Air Brakes Only)
(18) | Brake Cam Roller Pins at Interface of Pin and Shoe (Air Brakes Only)
(19) | Front Steering Knuckles
(20) | Front Wheel Bearings
(21) | Steering Tie Rod Ends
(22) | Clutch Release Cross Shaft (If Equipped)
(23) | Clutch Release Bearing (If Equipped)
(24) | Battery Terminal (Except ST type)
(25) | Transmission
(26) | Parking Brake Bell Crank (Hydraulic Brakes Only)
(27) | Parking Brake Lever Pivot (Hydraulic Brakes Only)
(28) | Propshaft Slip Joint
(29) | Propshaft Slip Joint
(30) | Rear Wheel Bearing
(31) | Brake Cam Roller Pins at Interface of Pin and Shoe (Air Brakes Only)
(32) | Brake Camshaft Brake Caliper Rails (If Equipped)
(33) | Slack Adjuster (Air Brakes Only)
(34) | Rear Axle
(35) | Spring Slip Pads (If Equipped with Multi-Leaf)
(35) | Spring Slip Pads (Multi-Leaf Spring Only)
(36) | Slack Adjuster (Air Brakes Only)
(37) | Brake Camshaft Brake Caliper Rails (If Equipped)
(38) | Brake Cam Roller Pins at Interface of Pin and Shoe (Air Brakes Only)
(39) | Rear Wheel Bearing

#### Tandem Axle Models

(1) | Propshaft U-Joint
(2) | Brake Camshafts
(3) | Brake Shoe Roller Pins
(4) | Rear Spring Pin
(5) | Wheel Bearing
(6) | Rear Axles
(7) | Propshaft Slip Joint
(8) | Propshaft U-Joint
(9) | Wheel Bearing
(10) | Rear Spring Pin
(11) | Brake Camshafts
(12) | Rear Axle
(13) | Brake Camshafts
(14) | Brake Shoe Roller Pins
(15) | Wheel Bearings
(16) | Propshaft U-Joint
(17) | Rear Spring Pin
(18) | Wheel Bearing
(19) | Brake Shoe Roller Pins
(20) | Brake Camshafts

#### 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 the temperature of the ball joints is -12°C (10°F) 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 any grease, do not apply any more grease. Allow time for the grease to bleed from the seal.

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

### Footnotes

[Dagger] The U.S. Environmental Protection Agency or the California Air Resources Board has determined that the failure to perform this maintenance item will not nullify the emission warranty or limit recall liability prior to the completion of the vehicle's useful life. It is recommended that all maintenance services be performed at the indicated intervals and the maintenance be recorded.

1. If the vehicle has an Allison® automatic transmission, the GM owner's manual is supplemented by an Allison Transmission Operator's Manual. Always refer to these manuals for related maintenance services.
2. Check the fluid level in the manual transmission.
3. This is an emission control service.
4. This is a noise emission control device.
5. This applies only to vehicles sold in the United States.
6. Inspect the fluid level in the following components:

• | Brake master cylinder. A low fluid level in the brake master cylinder may indicate worn brake linings and should be inspected.

• | Clutch master cylinder, if equipped

• | Power steering pump

• | Axle

• | Transmission

• | Hydraulic spring parking brake pump, if equipped

• | A low fluid level in the brake master cylinder can indicate worn brake linings and should be checked accordingly.

7. Inspect the following brake components:

• | Inspect the brake lines and the hoses for the following conditions:

- | Proper hookup

- | Binding

- | Leaks

- | Cracks

- | Chafing

• | The disc brake pads for wear

• | The rotors for surface condition

• | The brake pedal for excessive free play or travel - or every 6 months, whichever occurs first. Perform the brake pedal service, if necessary.

• | Inspect the brakes more often if driving habits and conditions result in frequent braking.

Important: The spring brake section of the actuator is NOT serviceable.

8. Inspect the hydraulic parking brake drum and the linings for wear or cracks. Inspect the linkage and the adjustment. Inspect the spring brake actuator and the pump for leaks.
9. This vehicle has an Engine Oil Life Monitor. This monitor will indicate when to change the engine oil and filter, usually between 5 000 km (3,000 mi) and 12 500 km (7,500 mi) since the last oil change.

• | Under severe conditions, the indicator may come on before 5 000 km (3,000 mi).

• | The vehicle should never be driven more than 12 500 km (7,500 mi) without an oil and filter change.

• | The system will not detect dust in the oil. If the vehicle is driven in dusty areas, be sure to change the oil and filter every 5 000 km (3,000 mi) or sooner if the Change Oil Light comes on.

• | Reset the Oil Life Monitor whenever the oil is changed.

10. Inspect the clutch pedal for free travel. Use the following procedure:

10.1. | Press the pedal using your hand until resistance is felt.

10.2. | Maintain free travel at 38-51 mm (1.5-2.0 in) measured at the clutch pedal pad.

10.3. | Inspect the clutch pedal for free travel at 5 000 km (3,000 mi) and 10 000 km (6,000 mi) and then every 10 000 km (6,000 mi) thereafter.

Inspect the clutch pedal for free travel at 4 000 km (2,500 mi) and 8 000 km (5,000 mi) and then every 8 000 km (5,000 mi) thereafter.

11. Inspect the rear axle air shift motor for fluid leaks. Use the following procedure:

11.1. | Remove the plug in order to inspect the fluid level.

11.2. | Inspect the air lines and the hoses for the following conditions:

• | Proper hookup

• | Binding

• | Leaks

11.3. | Inspect the rear axle air shift motor at 5 000 km (3,000 mi) and 40 000 km (24,000 mi) and then every 40 000 km (24,000 mi) thereafter.

Diesel Only: Inspect the rear axle air shift motor at 4 000 km (2,500 mi) and 40 000 km (25,000 mi) and then every 40 000 km (25,000 mi) thereafter.

12. Chassis Lubrication: Lubricate all the grease fittings in the front suspension, the front axle, and the steering linkage and steering gear at output shaft sleeve bearing.

Lubricate the suspension, axle and steering linkage more often when operating under dusty or muddy conditions and in excessive off-road use.

DO NOT lubricate the kingpin bushings with air pressure equipment. Use a hand-held grease gun in order to ensure complete purge and eliminate sealer cap distortion.

Lubricate the following components:

• | The transmission and the shift linkage

• | The hood latches and the hinges

• | The parking brake lever pivot

• | The clevis pins and the linkage

• | The disc brake caliper rails

• | The clutch linkage and release bearing, if equipped

• | The propeller shaft slip joint

• | The universal joint

• | The brake camshaft bracket

• | The slack adjusters

• | The pedal shaft

• | The clutch cross shaft

• | The clutch pedal springs

13. Inspect the steering the system for damaged, loose or missing parts. Inspect for parts showing signs of wear or lack of lubrication. Replace parts as needed.

Inspect the following components:

• | The steering gear mounting bolts. Tighten if necessary.

• | The pitman arm nut. Tighten if necessary.

• | The gear housing upper cover and the side cover attaching bolts. Tighten if necessary.

• | Steering column mounting bolts and cardan joint clamp bolts; tighten if necessary.

• | The power steering hoses, tubes, and the fittings for leaks. Ensure that the hoses and lines are not twisted, kinked or tightly bent.

• | Ensure that the following components are in the proper locations and are secure:

- | The clips

- | The clamps

- | The supporting tubes

- | The hoses

• | The steering gear for leakage around the pitman shaft and housing. If leakage is evident - lubrication oozing out, not just an oily film, repair the leak immediately.

14. Inspect the front and the rear suspension for the following conditions: damaged, loose or missing parts, or parts showing signs of wear or lack of lubrication. Replace the parts as necessary.
15. Adjust the tire pressure as indicated in the GM Owner's Manual for optimum tire life.

Inspect the tires for excessive or abnormal wear or damage. Inspect for damaged wheels. Replace the wheels and/or tires as needed.

16. Inspect the spring-to-axle U-bolts and the shackle bolts for the proper torque.

When the vehicle is new or when parts are replaced, inspect and adjust the torque more often during the first 10 000 km (6,000 mi). Inspect the torque at 800 km (500 mi) and 3 000 km (2,000 mi) after the parts are first used.

17. In order to maintain exhaust system integrity, replace the exhaust pipes whenever a new muffler is installed.

Inspect the complete exhaust system and the cab areas near the exhaust system for the following conditions. Perform any needed repairs immediately.

• | Broken parts

• | Damaged parts

• | Missing parts

• | Out of position parts

• | Open seams

• | Holes

• | Loose connections

• | Other conditions which may permit exhaust fumes to seep into the driver compartment

18. Inspect all of the engine drive belts for the following conditions. Adjust or replace the drive belts as necessary.

• | Cracks

• | Fraying

• | Wear

19. With the engine OFF and below normal operating temperature, verify that the thermostatically controlled engine cooling fan can be rotated using your hand on viscous-operated drives. Replace as needed.
20. Inspect the shields and the underhood insulation for damage or looseness. Adjust or replace as needed.
21. Lubricate the following components:

• | The caliper housing

• | The caliper support spring

• | The caliper support key

22. Wheel bearing service:

Grease type: Clean, inspect and lubricate the wheel bearing using the proper wheel bearing grease at designated intervals or whenever the hubs are removed.

Oil-filled type: Some wheel bearings are lubricated by rear axle lubricant. If you have oil-filled hubs, use lubricant identical to the lubricant used in your rear axle. Lubricant change intervals are the same for the front and the rear axles. Maintain the oil level at the OIL LEVEL mark between change intervals.

23. Inspect the air intake system installation in order to ensure that the gaskets are seated properly and all of the hose connections, fasteners and other components are tight.

Tighten the connections and the fasteners or replace the parts as necessary.

For gasoline engines ensure that the following conditions are true:

• | The air cleaner housing is properly seated.

• | The cover fits tightly.

• | The wing nut is tight.

24. Evaporative Control System Service (if equipped). Inspect the following items and replace the parts as necessary:

• | The fuel and the vapor lines and the hoses for proper connection and correct routing.

• | The fuel and vapor lines and the hoses.

• | Correct routing of lines and hoses.

25. Replace the air cleaner filter - or every 24 months, whichever occurs first. Replace the filter more often if driving in dusty conditions. Ask your dealer for the proper replacement intervals for your driving conditions.
26. Replace the spark plugs Inspect the wires for damage. Inspect the wire boot and the boot heat shield fit at the spark plugs and the distributor. Replace parts as needed.
27. Perform the following inspections. Replace the parts as necessary.

• | Inspect the following components for damage which may cause leakage:

- | The fuel tank

- | The fuel cap

- | The fuel lines

• | Inspect the fuel cap for proper sealing ability and damage.

• | Inspect the fuel cap gasket for an even filter neck imprint.

28. Inspect the Electronic Vacuum Regulator Valve (EVRV) filter for excessive contamination or plugging. Clean the filter using a solution of soap and water, if necessary. Let the filter dry and install.
29. Drain, flush, and refill the cooling system.

29.1. | Inspect the hoses.

29.2. | Clean the radiator.

29.3. | Clean the condenser.

29.4. | Clean the pressure cap and the neck.

29.5. | Pressure test the cooling system and the pressure cap.

30. Perform rear axle service change the lubricant.
31. Perform the front axle service: Re-pack the upper kingpin roller bearing.

Important: The spring brake section of the rear brake diaphragms are NOT serviceable.

Check brakes more often if driving habits and conditions result in frequent braking.
32. Perform the following air brake service:

• | Inspect brake parts at each wheel, including drums, wheel cylinders and piston heat shields and boots. Check brake pedal for excessive free play or travel - or every 6 months, whichever occurs first.

• | Inspect the both air and drum brake lines, hoses for the following:

- | Proper hook-up

- | Binding

- | Leaks

- | Cracks

- | Chafing

- | Wear

• | Test air lines for leaks; tighten as needed

• | Replace the compressor filter.

• | Check all attachments for tightness, wear or damage.

• | Inspect air parking brake chamber and the lines and hoses for the following:

- | Leaks

- | Damage

- | Cracks

- | Chafing

• | Replace the air compressor filter element, mounted on the air compressor.

• | For remote air compressor intake service, refer to air cleaner filter replacement (25).

33. Clean and lubricate the air brake automatic slack adjuster. Inspect the pushrod travel and the auto adjustment operation. Perform the slack adjuster service, if necessary.
34. Inspect the operation of the air brake chamber and the following components. Inspect the air brake chamber for leaks.

• | The mounting

• | The clamps

• | The air lines

35. Verify operation of the trailer brake hand control valve. Lubricate the cam and the follower.
36. Remove, disassemble, clean, and inspect the following air brake components. Replace any parts showing wear.

• | The safety valve

• | The standard brake chamber

• | The quick release valve

• | The quick release/double check valve combination

• | The parking brake control valve

• | The double check valve

• | The spring brake control valve. Replace any rubber parts.

37. Tighten the wheel stud nuts to the specified torque values at 160 km (100 mi), 800 km (500 mi) and 1 600 km (1,000 mi) and then every 1 600 km (1,000 mi) thereafter.
38. Service is required now if the vehicle is operated under any of the Short Trip/City conditions:

• | Most trips are less than 8 to 16 km (5 to 10 mi). This is particularly important when outside temperatures are below freezing.

• | Most trips are through dusty areas.

• | Vehicle frequently tow a trailer.

• | The vehicle is operated at or near maximum GVW ratings.

• | The vehicle is operated in hilly or mountainous terrain.

39. Service is required now for all vehicles that have not previously required service under the Short/Trip City conditions.