GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1999 🢒 GMC C-Series Medium Duty Truck B7 🢒 General Information 🢒 Maintenance and Lubrication 🢒 Explanation of Scheduled Services
  1. Short Trip/City Maintenance Schedule.
  2. Long Trip/Highway Maintenance Schedule.
  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:
    7. • 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
  7. Inspect the following brake components:
    8. • 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 drum brake linings for wear or cracks
    • The drums
    • The wheel cylinders
    • The piston heat shields and the boots
    • Other brake parts
    • 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. All Engines Except 6.5L

    • For the Short Trip/City Maintenance Schedule (1), change the engine oil and the filter every 5 000 km (3,000 mi) or 3 months, whichever occurs first for all engines except 6.5L.
    • For the Long Trip/Highway Maintenance Schedule (2), change the engine oil and the filter every 10 000 km (6,000 mi) or 6 months, whichever occurs first for all engines except 6.5L.
    • For gasoline engines, refer to your GM Owner's Manual for details on engine oil.
    • For diesel engines, refer to the Caterpillar® 3126 Diesel Engine Operation & Maintenance Manual for oil recommendations and change intervals.

    6.5L

    • For the Short Trip/City Maintenance Schedule (1), change the engine oil and the filter every 4 000 km (2,500 mi) or 3 months, whichever occurs first.
    • For the Long Trip/Highway Maintenance Schedule (2), change the engine oil and the filter every 8 000 km (5,000 mi) or 6 months, whichever occurs first.
  9. Inspect the clutch pedal for free travel. Use the following procedure:
    10. 9.1. Press the pedal using your hand until resistance is felt.
    9.2. Maintain free travel at 38-51 mm (1.5-2.0 in) measured at the clutch pedal pad.
    9.3. 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.

    6.5L: 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.

  10. Inspect the rear axle air shift motor for fluid leaks. Use the following procedure:
    11. 10.1. Remove the plug in order to inspect the fluid level.
    10.2. Inspect the air lines and the hoses for the following conditions:
       • Proper hookup
       • Binding
       • Leaks
    10.3. 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.

    B7 Model -- 6.5L 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.

  11. Lubricate all the grease fittings in the front suspension, the front axle, and the steering linkage.

    12. Lubricate the suspension, the axle and the 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
  12. 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.

    13. 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.
    • The steering column mounting 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.
  13. 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.
    14. • Damaged parts
    • Missing parts
    • Parts showing signs of wear
    • Lack of lubrication
  14. Adjust the tire pressure as indicated in the GM Owner's Manual for optimum tire life.

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

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

    16. 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.

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

    17. 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
  17. Inspect all of the engine drive belts for the following conditions. Adjust or replace the drive belts as necessary.
    18. • Cracks
    • Fraying
    • Wear
    • Proper tension
  18. Do not lubricate the accelerator and the cruise control cables.

    19. Inspect the throttle linkage for the following conditions. Perform any needed repairs immediately.

    • Damaged parts (including throttle return springs)
    • Missing parts (including throttle return springs)
    • Interference
    • Binding
  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:
    22. • The brake caliper V-ways
    • The brake caliper retainer
    • The brake caliper retainer spring
  22. Grease type: Clean, inspect and lubricate the wheel bearing using the proper wheel bearing grease at designated intervals or whenever the hubs are removed.

    23. 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.

    24. 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. Inspect the thermostatically controlled air cleaner installation in order to ensure that all of the ducts are connected and properly installed. Verify the proper operation of the check valve.
  25. Inspect the following items. Replace the parts as necessary:
    26. • 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.
  26. Replace the filter more often if driving in dusty conditions. Ask your dealer for the proper replacement intervals for your driving conditions.
  27. 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.
  28. Adjust the ignition timing to the underhood label specifications.

    29. Inspect the interior and the exterior of the following components for cracks or terminal corrosion. Clean or replace the parts as necessary.

    • The distributor cap
    • The distributor rotor and the coil
  29. Perform the following inspections. Replace the parts as necessary.
    30. • 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.
  30. Inspect the EGR system as described in this service manual.
  31. 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.
  32. Verify proper operation of the PCV system. Clean the PCV valve. Replace the hoses as necessary.
  33. Replace the PCV valve. Blow out the PCV valve hose using compressed air. Replace the hoses as necessary.
  34. Drain, flush, and refill the cooling system.
    35. 34.1. Inspect the hoses.
    34.2. Clean the radiator.
    34.3. Clean the condenser.
    34.4. Clean the pressure cap and the neck.
    34.5. Pressure test the cooling system and the pressure cap.
  35. Not applicable
  36. Perform rear axle service change the lubricant.
  37. Repack the upper kingpin roller bearing.

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

  38. Perform the following steps:

    39. Inspect the air parking brake chamber for leaks and damage. Inspect the lines and the hoses for leaks, cracks, and chafing. Inspect all of the attachments for tightness, wear or damage.

    Replace the air compressor filter element, mounted on the air compressor. For remote air compressor intake service, refer to Air Cleaner Filter Replacement.

    Lubricate the air brake manual slack adjuster at the chassis. Inspect the pushrod travel. Adjust the pushrod if necessary. Perform the following steps:

    • Test the air lines for leaks.
    • Tighten the air lines as necessary.
    • Replace the compressor filter.
    • Inspect the air parking brake chamber for leaks and damage.
    • Inspect all of the hose attachments for the following conditions:
       - Tightness
       - Wear
       - Damage
    • Inspect the hoses and lines for the following conditions:
       - Leaks
       - Cracks
       - Chafing
  39. 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.
  40. Inspect the operation of the air brake chamber and the following components. Inspect the air brake chamber for leaks.
    41. • The mounting
    • The clamps
    • The air lines
  41. Verify operation of the trailer brake hand control valve. Lubricate the cam and the follower.
  42. Not applicable
  43. Remove, disassemble, clean, and inspect the following air brake components. Replace any parts showing wear.
    44. • 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.
  44. For Stud Piloted Wheels Only: 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.
  45. For Hub Piloted Wheels Only: Tighten the wheel stud nuts to the specified torque values at 1 600 km (1,000 mi). Thereafter, tighten the wheel stud nuts 1 600 km (1,000 mi) after each time the wheel is removed. Refer to Fasteners
  46. If your vehicle has an Allison automatic transmission, your GM Owner's Manual is supplemented by an Allison Transmission Operator's Manual. Always refer to these manuals for related maintenance services.
  47. Check the fluid level in the manual transmission.