Hummer Maintenance Schedule

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This schedule lists the maintenance services which are necessary for the proper operation, safety, and performance of your vehicle. It is important to perform these services at the scheduled intervals. Without routine maintenance your vehicle's longevity and reliability can be greatly reduced. The maintenance intervals may be affected by the type of environment in which you are driving. For example, operating in mud or sand will require more frequent lubrication and fluid servicing.

Maintenance Inspection Groups A-B-C

The inspection groups outline additional components to be checked at stated mileage intervals. Perform necessary service repair, replacement, or adjustments as each inspection item is checked.

Maintenance Inspection Group A consists of the following items:
  • Check fluid levels & condition for power steering pump, cooling system(reservoir & surge tank), brakes, transmission, transfer case, geared hubs, and axles.
  • Check CDR valve for oil saturation (diesel).
  • Inspect condition of control arms, springs, & shock absorbers.
  • Check tire wear & condition.
  • Lubricate all grease fittings & body lubrication points.
  • Inspect geared hubs for leaking seals or damage.
  • Inspect service brakes & parking brake.
  • Check axles for leaks or damage.
  • Check wheels bolt & nut torque.
  • Inspect condition of geared hub & axle vent lines.
  • Inspect condition of transmission & transfer case vent lines.
  • Inspect U-joints for wear or missing/damaged grease fittings.
  • Inspect transmission/transfer case shift linkage for wear, binding, and/or distortion.
  • On gas engines and non-turbo models, inspect accelerator linkage for wear, binding, loose, and/or excessive play.
  • Inspect condition of engine mounts & insulators.
  • Check ignition timing (gas engine only).
  • Check fuel filter and drain/clean if necessary (diesel).
  • Check CTIS operation. Verify that system inflates/deflates tires.
Maintenance Inspection Group B consists of the following items:
  • Inspect fuel injection pump, lines, & fittings for leaks or damage (diesel).
  • Check battery voltage & condition. Clean battery exterior with ammonia/water or baking soda/water mixture.
  • Inspect serpentine belt condition.
  • Inspect exhaust system & shields.
  • Inspect & rotate tires.
  • Inspect halfshaft boots & ball joint seals.
  • Inspect condition of steering column, U-joints, tie rods, steering arm. center link, & idler arm.
  • Check fuel tank vent line filter.
  • Inspect condition of frame rails & cross-members.
  • Check A/C system operation.
  • Check Wheel Alignment
Maintenance Inspection Group C consists of the following items:
  • Inspect surge tank, radiator & shroud, A/C condenser, power steering & transmission coolers, & all hoses & fittings for security of mounting, leaks, or damage.
  • Inspect fuel tank, lines, & cap.
  • Inspect all wiring harnesses for frays, splits, missing insulation, poor connections.
  • Inspect power steering pump, power steering gear, hoses, lines, & fittings for leaks or damage.
  • Check ignition wires (gas).


 3,000 (15,000)

  • Maintenance Group A
  • Change oil & filter.
  • Inspect idler arm.
  • Inspect pitman arm.
  • Inspect halfshaft bolts.
  • A/C performance check.



  • Maintenance Group A
  • Change oil & filter.
  • Inspect idler arm.
  • Inspect pitman arm.
  • Inspect halfshaft bolts.
  • A/C performance check.
  • Replace fuel filter.


  • Maintenance Group A
  • Maintenance Group B
  • Maintenance Group C
  • Change oil & filter.
  • Flush coolant system
  • Service transmission.
  • Inspect idler arm.
  • Inspect pitman arm.
  • Inspect halfshaft bolts.
  • A/C performance check.
  • Rotate & balance tires.
  • Change fuel filter???
  • Service air filter.
  • Service transfer case.
  • Check alignment.
  • Check batteries at 24,000 miles.

At 27,000 miles, repeat the cycle starting with the 3,000 mile service continuing down the list every 3,000 miles. If your vehicle is over 24,000 miles and hasn't been serviced in a while, begin with the 12,000 mile service and rotate back to the 3,000 mile service after the next 3,000 miles.

Items in Red are recommended by Flash Off-Road

** This information is from the HUMMER® Recommended Maintenance Schedule (#0574480)