The services shown in this schedule up to 100,000 miles (166 000 km) should be repeated after 100,000 miles (166 000 km) at the same intervals for the life of this vehicle. The services shown after 100,000 miles (166 000 km) should be repeated at the same miles (km) after those intervals for the life of this vehicle.

Gasoline engine vehicles and some DURAMAX® diesel engine vehicles have a computer that lets you know when to change your engine oil. This is not based on mileage, but on engine operation and engine temperature. When the computer has calculated that the oil needs changing, the Engine Oil Life System will indicate that a change is necessary. See Engine Oil Life System .

The "Footnotes" at the end of this Maintenance Schedule further explain maintenance services.

See Service Publications Ordering Information .

•	Wheel stud nut service. (36)

•	Wheel stud nut service. (36)

•	Rear axle air shift motor service. (10)

•	Gasoline Engine Only: Check engine oil life system. If engine oil and filter are changed, reset system. See "Engine Oil (Gasoline Engine)" in the Index. (2) (8)

•	Check fluid levels (or every 3 months, whichever occurs first). (1) (5)

•	Chassis lubrication service (or every 6 months, whichever occurs first).(11)

•	Wheels and tires service. (14)

•	Hydraulic brake service (or every 6 months, whichever occurs first). (6) (36)

•	Parking brake service (or every 6 months, whichever occurs first). (21)

•	Air brake service (or every 6 months, whichever occurs first). (32)

•	Air brake automatic slack adjuster service (or every 500 hours, whichever occurs first). (33)

•	Check air brake relay valve operation and check for leaks (or every month, or every 300 hours, whichever occurs first).

•	Clean air brake application valve (or every 3 months, or every 300 hours, whichever occurs first). Lubricate linkage.

•	Air brake chamber service (or every 2 months, whichever occurs first).(34)

•	7.8L DURAMAX® Diesel Without Engine Oil Life System Only: Change engine oil and filter (or every 12 months, or every 600 hours of engine operation, whichever occurs first). (2)

•	7.8L DURAMAX® Diesel With Engine Oil Life System Only: Check oil life system (or every 12 months, or every 600 hours of engine operation, whichever occurs first). If engine oil and filter are changed, reset system. See "Engine Oil (DURAMAX® Diesel)" in the Index. (2) (7)

•	Gasoline Engine Only: Check engine oil life system. If engine oil and filter are changed, reset system. See "Engine Oil (Gasoline Engine)" in the Index. (2) (8)

•	6.6L DURAMAX® Diesel Without Engine Oil Life System Only: Change engine oil and filter (or every 12 months, or every 750 hours of engine operation, whichever occurs first). (2)

•	6.6L DURAMAX® Diesel With Engine Oil Life System Only: Check oil life system. If engine oil and filter are changed, reset system. See "Engine Oil (DURAMAX® Diesel)" in the Index. (2) (9)

•	Chassis lubrication service (or every 6 months, whichever occurs first).(11)

•	Check fluid levels (or every 3 months, whichever occurs first). (1) (5)

•	Gasoline Engine: Inspect engine air cleaner filter. If necessary, replace the filter. If vehicle is driven in dusty/dirty conditions, inspect filter at every engine oil change. See Engine Air Cleaner/Filter for more information.

•	Diesel Engine: Inspect engine air cleaner filter change indicator. If necessary, replace the filter. If vehicle is driven in dusty/dirty conditions, inspect filter change indicator at every engine oil change. See Engine Air Cleaner/Filter for more information.

•	DURAMAX® Diesel Only: Replace fuel filter (or every 750 hours of engine operation, whichever occurs first).

•	Steering system service. (12)

•	Front and rear suspension service. (13)

•	Spring-to-axle U-bolts and shackle bolts service. (15)

•	Exhaust system service (or every 6 months, whichever occurs first). (2) (3) (16)

•	Wheels and tires service. (14)

•	Hydraulic brake service (or every 6 months, whichever occurs first). (6) (36)

•	Parking brake service (or every 6 months, whichever occurs first). (21)

•	Air brake service (or every 6 months, whichever occurs first). (32)

•	Air brake automatic slack adjuster service (or every 500 hours, whichever occurs first). (33)

•	Check air brake relay valve operation and check for leaks (or every month, or every 300 hours, whichever occurs first).

•	Clean air brake application valve (or every 3 months, or every 300 hours, whichever occurs first). Lubricate linkage.

•	Air brake chamber service (or every 2 months, whichever occurs first).(34)

•	Thermostatically controlled engine cooling fan service. (3) (19)

•	Shields and underhood insulation service. (3) (4) (20)

•	Air compressor dry element pleated paper air strainer service (or every 2 months or every 800 hours, whichever occurs first).

•	Gasoline Engine Only: Check engine oil life system. If engine oil and filter are changed, reset system. See "Engine Oil (Gasoline Engine)" in the Index. (2) (8)

•	Check fluid levels (or every 3 months, whichever occurs first). (1) (5)

•	Chassis lubrication service (or every 6 months, whichever occurs first).(11)

•	Inspect door hinge pins and bushings and replace as necessary.

•	Cooling system service. Clean the cooling system filter cap with clean water, clean the core, pressure test the cap and the system for proper pressure capability, and inspect condition of cooling and heater hoses and clamps. Replace hoses if cracked,,swollen, or damaged.

•	Wheel bearing (grease type) service (or every 24 months, whichever occurs first, and whenever hubs are removed). (22) (36)

•	Wheels and tires service. (14)

•	Hydraulic brake service (or every 6 months, whichever occurs first). (6) (36)

•	Parking brake service (or every 6 months, whichever occurs first). (21)

•	Air brake service (or every 6 months, whichever occurs first). (32)

•	Air brake automatic slack adjuster service (or every 500 hours, whichever occurs first). (33)

•	Check air brake relay valve operation and check for leaks (or every month, or every 300 hours, whichever occurs first).

•	Clean air brake application valve (or every 3 months, or every 300 hours, whichever occurs first). Lubricate linkage.

•	Air brake chamber service (or every 2 months, whichever occurs first).(34)

•	Air brake system valve service (or every 3 months, or every 900 hours, whichever occurs first). (37)

•	Air intake system service (or every 24 months, whichever occurs first).(3) (4) (23)

•	Evaporative Control System service, if equipped, (or every 24 months, whichever occurs first). (2) (24) †

•	Rear axle air shift motor service. (10)

•	7.8L DURAMAX® Diesel Without Engine Oil Life System Only: Change engine oil and filter (or every 12 months, or every 600 hours of engine operation, whichever occurs first). (2)

•	7.8L DURAMAX® Diesel With Engine Oil Life System Only: Check oil life system (or every 12 months, or every 600 hours of engine operation, whichever occurs first). If engine oil and filter are changed, reset system. See "Engine Oil (DURAMAX® Diesel)" in the Index. (2) (7)

•	Gasoline Engine Only: Check engine oil life system. If engine oil and filter are changed, reset system. See "Engine Oil (Gasoline Engine)" in the Index. (2) (8)

•	6.6L DURAMAX® Diesel Without Engine Oil Life System Only: Change engine oil and filter (or every 12 months, or every 750 hours of engine operation, whichever occurs first). (2)

•	6.6L DURAMAX® Diesel With Engine Oil Life System Only: Check oil life system. If engine oil and filter are changed, reset system. See "Engine Oil (DURAMAX® Diesel)" in the Index. (2) (9)

•	Check fluid levels (or every 3 months, whichever occurs first). (1) (5)

•	Gasoline Engine: Inspect engine air cleaner filter. If necessary, replace the filter. If vehicle is driven in dusty/dirty conditions, inspect filter at every engine oil change. See Engine Air Cleaner/Filter for more information.

•	Diesel Engine: Inspect engine air cleaner filter change indicator. If necessary, replace the filter. If vehicle is driven in dusty/dirty conditions, inspect filter change indicator at every engine oil change. See Engine Air Cleaner/Filter for more information.

•	DURAMAX® Diesel Only: Replace fuel filter (or every 750 hours of engine operation, whichever occurs first).

•	Chassis lubrication service (or every 6 months, whichever occurs first).(11)

•	Replace fuel filter(s) (or every 12 months, whichever occurs first). (2)

•	Steering system service. (12)

•	Front and rear suspension service. (13)

•	Spring-to-axle U-bolts and shackle bolts service. (15)

•	Exhaust system service (or every 6 months, whichever occurs first). (2) (3) (16)

•	Wheels and tires service. (14)

•	Hydraulic brake service (or every 6 months, whichever occurs first). (6) (36)

•	Parking brake service (or every 6 months, whichever occurs first). (21)

•	Air brake service (or every 6 months, whichever occurs first). (32)

•	Air brake automatic slack adjuster service (or every 500 hours, whichever occurs first). (33)

•	Check air brake relay valve operation and check for leaks (or every month, or every 300 hours, whichever occurs first).

•	Clean air brake application valve (or every 3 months, or every 300 hours, whichever occurs first). Lubricate linkage.

•	Air brake chamber service (or every 2 months, whichever occurs first).(34)

•	C600, C700, and C800 Gasoline Engines Only: Engine drive belts service (or every 12 months, whichever occurs first.) (17)

•	Thermostatically controlled engine cooling fan service. (3) (19)

•	Shields and underhood insulation service. (3) (4) (20)

•	Air compressor dry element pleated paper air strainer service (or every 2 months or every 800 hours, whichever occurs first).

•	7.8L DURAMAX® Diesel Without Engine Oil Life System Only: Change engine oil and filter (or every 12 months, or every 600 hours of engine operation, whichever occurs first). (2)

•	7.8L DURAMAX® Diesel With Engine Oil Life System Only: Check oil life system (or every 12 months, or every 600 hours of engine operation, whichever occurs first). If engine oil and filter are changed, reset system. See "Engine Oil (DURAMAX® Diesel)" in the Index. (2) (7)

•	Gasoline Engine Only: Check engine oil life system. If engine oil and filter are changed, reset system. See "Engine Oil (Gasoline Engine)" in the Index. (2) (8)

•	Check fluid levels (or every 3 months, whichever occurs first). (1) (5)

•	Chassis lubrication service (or every 6 months, whichever occurs first).(11)

•	Wheels and tires service. (14)

•	Hydraulic brake service (or every 6 months, whichever occurs first). (6) (36)

•	Parking brake service (or every 6 months, whichever occurs first). (21)

•	Air brake service (or every 6 months, whichever occurs first). (32)

•	Air brake automatic slack adjuster service (or every 500 hours, whichever occurs first). (33)

•	Check air brake relay valve operation and check for leaks (or every month, or every 300 hours, whichever occurs first).

•	Clean air brake application valve (or every 3 months, or every 300 hours, whichever occurs first). Lubricate linkage.

•	Air brake chamber service (or every 2 months, whichever occurs first).(34)

•	Gasoline Engine Only: Check engine oil life system. If engine oil and filter are changed, reset system. See "Engine Oil (Gasoline Engine)" in the Index. (2) (8)

•	6.6L DURAMAX® Diesel Without Engine Oil Life System Only: Change engine oil and filter (or every 12 months, or every 750 hours of engine operation, whichever occurs first). (2)

•	6.6L DURAMAX® Diesel With Engine Oil Life System Only: Check oil life system. If engine oil and filter are changed, reset system. See "Engine Oil (DURAMAX® Diesel)" in the Index. (2) (9)

•	Check fluid levels (or every 3 months, whichever occurs first). (1) (5)

•	Gasoline Engine: Replace engine air cleaner filter. See Engine Air Cleaner/Filter for more information.

•	Diesel Engine: Inspect engine air cleaner filter change indicator. If necessary, replace the filter. If vehicle is driven in dusty/dirty conditions, inspect filter change indicator at every engine oil change. See Engine Air Cleaner/Filter for more information.

•	DURAMAX® Diesel Only: Replace fuel filter (or every 750 hours of engine operation, whichever occurs first).

•	Chassis lubrication service (or every 6 months, whichever occurs first).(11)

•	Cooling system service. Clean the cooling system filler cap with clean water, clean the core, pressure test the cap and the system for proper pressure capability, and inspect condition of cooling and heater hoses and clamps. Replace hoses if cracked, swollen, or damaged.

•	Wheel bearing (grease type) service (or every 24 months, whichever occurs first, and whenever hubs are removed.) (22) (36)

•	Inspect door hinge pins and bushings and replace as necessary.

•	Steering system service. (12)

•	Front and rear suspension service. (13)

•	Spring-to-axle U-bolts and shackle bolts service. (15)

•	Exhaust system service (or every 6 months, whichever occurs first). (2) (3) (16)

•	Wheels and tires service. (14)

•	Hydraulic brake service (or every 6 months, whichever occurs first). (6) (36)

•	Parking brake service (or every 6 months, whichever occurs first). (21)

•	Air brake service (or every 6 months, whichever occurs first). (32)

•	Air brake automatic slack adjuster service (or every 500 hours, whichever occurs first). (33)

•	Check air brake relay valve operation and check for leaks (or every month, or every 300 hours, whichever occurs first).

•	Clean air brake application valve (or every 3 months, or every 300 hours, whichever occurs first). Lubricate linkage.

•	Air brake chamber service (or every 2 months, whichever occurs first).(34)

•	Air brake system valve service (or every 3 months, or every 900 hours, whichever occurs first). (37)

•	Thermostatically controlled engine cooling fan service. (3) (19)

•	Shields and underhood insulation service. (3) (4) (20)

•	Rear axle air shift motor service. (10)

•	Air intake system service (or every 24 months, whichever occurs first).(3) (4) (23)

•	Evaporative Control System service, if equipped, (or every 24 months, whichever occurs first). (2) (24) †

•	Air compressor dry element pleated paper air strainer service (or every 2 months or every 800 hours, whichever occurs first).

•	7.8L DURAMAX® Diesel Without Engine Oil Life System Only: Change engine oil and filter (or every 12 months, or every 600 hours of engine operation, whichever occurs first). (2)

•	7.8L DURAMAX® Diesel With Engine Oil Life System Only: Check oil life system (or every 12 months, or every 600 hours of engine operation, whichever occurs first). If engine oil and filter are changed, reset system. See "Engine Oil (DURAMAX® Diesel)" in the Index. (2) (7)

•	Inspect air compressor discharge port (or every 6 months or every 1,800 hours, whichever occurs first.)

•	Gasoline Engine Only: Check engine oil life system. If engine oil and filter are changed, reset system. See "Engine Oil (Gasoline Engine)" in the Index. (2) (8)

•	Check fluid levels (or every 3 months, whichever occurs first). (1) (5)

•	Chassis lubrication service (or every 6 months, whichever occurs first).(11)

•	Wheels and tires service. (14)

•	DURAMAX® Diesel Engine Only: Adjust valve lash (or every 2,625 hours of engine operation, whichever occurs first). (18)

•	Hydraulic brake service (or every 6 months, whichever occurs first). (6) (36)

•	Parking brake service (or every 6 months, whichever occurs first). (21)

•	Air brake service (or every 6 months, whichever occurs first). (32)

•	Air brake automatic slack adjuster service (or every 500 hours, whichever occurs first). (33)

•	Check air brake relay valve operation and check for leaks (or every month, or every 300 hours, whichever occurs first).

•	Clean air brake application valve (or every 3 months, or every 300 hours, whichever occurs first). Lubricate linkage.

•	Air brake chamber service (or every 2 months, whichever occurs first).(34)

•	Gasoline Engine Only: Check engine oil life system. If engine oil and filter are changed, reset system. See "Engine Oil (Gasoline Engine)" in the Index. (2) (8)

•	6.6L DURAMAX® Diesel Without Engine Oil Life System Only: Change engine oil and filter (or every 12 months, or every 750 hours of engine operation, whichever occurs first). (2)

•	6.6L DURAMAX® Diesel With Engine Oil Life System Only: Check oil life system. If engine oil and filter are changed, reset system. See "Engine Oil (DURAMAX® Diesel)" in the Index. (2) (9)

•	7.8L DURAMAX® Diesel Without Engine Oil Life System Only: Change engine oil and filter (or every 12 months, or every 600 hours of engine operation, whichever occurs first). (2)

•	7.8L DURAMAX® Diesel With Engine Oil Life System Only: Check oil life system (or every 12 months, or every 600 hours of engine operation, whichever occurs first). If engine oil and filter are changed, reset system. See "Engine Oil (DURAMAX® Diesel)" in the Index. (2) (7)

•	Gasoline Engine Only (Vehicles with GVW greater than 16,000 lbs): Spark plug service. (2) (25)

•	Check fluid levels (or every 3 months, whichever occurs first). (1) (5)

•	Gasoline Engine: Inspect engine air cleaner filter. If necessary, replace the filter. If vehicle is driven in dusty/dirty conditions, inspect filter at every engine oil change. See Engine Air Cleaner/Filter for more information.

•	Diesel Engine: Inspect engine air cleaner filter change indicator. If necessary, replace the filter. If vehicle is driven in dusty/dirty conditions, inspect filter change indicator at every engine oil change. See Engine Air Cleaner/Filter for more information.

•	DURAMAX® Diesel Only: Replace fuel filter (or every 750 hours of engine operation, whichever occurs first).

•	Chassis lubrication service (or every 6 months, whichever occurs first).(11)

•	Replace fuel filter(s) (or every 12 months, whichever occurs first). (2)

•	Inspect door hinge pins and bushings and replace as necessary.

•	Steering system service. (12)

•	Front and rear suspension service. (13)

•	Spring-to-axle U-bolts and shackle bolts service. (15)

•	Exhaust system service (or every 6 months, whichever occurs first). (2) (3) (16)

•	Wheels and tires service. (14)

•	Hydraulic brake service (or every 6 months, whichever occurs first). (6) (36)

•	Parking brake service (or every 6 months, whichever occurs first). (21)

•	Air brake service (or every 6 months, whichever occurs first). (32)

•	Air brake automatic slack adjuster service (or every 500 hours, whichever occurs first). (33)

•	Check air brake relay valve operation and check for leaks (or every month, or every 300 hours, whichever occurs first).

•	Clean air brake application valve (or every 3 months, or every 300 hours, whichever occurs first). Lubricate linkage.

•	Air brake chamber service (or every 2 months, whichever occurs first).(34)

•	C600, C700, and C800 Gasoline Engines Only: Engine drive belts service (or every 12 months, whichever occurs first). (17)

•	Thermostatically controlled engine cooling fan service. (3) (19)

•	Shields and underhood insulation service. (3) (4) (20)

•	Air compressor dry element pleated paper air strainer service (or every 2 months or every 800 hours, whichever occurs first).

•	Gasoline Engine Only: Check engine oil life system. If engine oil and filter are changed, reset system. See "Engine Oil (Gasoline Engine)" in the Index. (2) (8)

•	Check fluid levels (or every 3 months, whichever occurs first). (1) (5)

•	Chassis lubrication service (or every 6 months, whichever occurs first).(11)

•	Cooling system service. Clean the cooling system filler cap with clean water, clean the core, pressure test the cap and the system for proper pressure capability, and inspect condition of cooling and heater hoses and clamps. Replace hoses if cracked, swollen, or damaged.

•	Wheel bearing (grease type) service (or every 24 months, whichever occurs first, and whenever hubs are removed). (22) (36)

•	Wheels and tires service. (14)

•	Hydraulic brake service (or every 6 months, whichever occurs first). (6) (36)

•	Parking brake service (or every 6 months, whichever occurs first). (21)

•	Air brake service (or every 6 months, whichever occurs first). (32)

•	Air brake automatic slack adjuster service (or every 500 hours, whichever occurs first). (33)

•	Check air brake relay valve operation and check for leaks (or every month, or every 300 hours, whichever occurs first).

•	Clean air brake application valve (or every 3 months, or every 300 hours, whichever occurs first). Lubricate linkage.

•	Air brake chamber service (or every 2 months, whichever occurs first).(34)

•	Air brake system valve service (or every 3 months, or every 900 hours, whichever occurs first). (37)

•	Rear axle air shift motor service. (10)

•	Air intake system service (or every 24 months, whichever occurs first).(3) (4) (23)

•	Evaporative Control System service, if equipped, (or every 24 months, whichever occurs first). (2) (24) †

•	7.8L DURAMAX® Diesel Without Engine Oil Life System Only: Change engine oil and filter (or every 12 months, or every 600 hours of engine operation, whichever occurs first). (2)

•	7.8L DURAMAX® Diesel With Engine Oil Life System Only: Check oil life system (or every 12 months, or every 600 hours of engine operation, whichever occurs first). If engine oil and filter are changed, reset system. See "Engine Oil (DURAMAX® Diesel)" in the Index. (2) (7)

•	Gasoline Engine Only: Check engine oil life system. If engine oil and filter are changed, reset system. See "Engine Oil (Gasoline Engine)" in the Index. (2) (8)

•	6.6L DURAMAX® Diesel Without Engine Oil Life System Only: Change engine oil and filter (or every 12 months, or every 750 hours of engine operation, whichever occurs first). (2)

•	6.6L DURAMAX® Diesel With Engine Oil Life System Only: Check oil life system. If engine oil and filter are changed, reset system. See "Engine Oil (DURAMAX® Diesel)" in the Index. (2) (9)

•	Chassis lubrication service (or every 6 months, whichever occurs first).(11)

•	Check fluid levels (or every 3 months, whichever occurs first). (1) (5)

•	Gasoline Engine: Inspect engine air cleaner filter. If necessary, replace the filter. If vehicle is driven in dusty/dirty conditions, inspect filter at every engine oil change. See Engine Air Cleaner/Filter for more information.

•	Diesel Engine: Inspect engine air cleaner filter change indicator. If necessary, replace the filter. If vehicle is driven in dusty/dirty conditions, inspect filter change indicator at every engine oil change. See Engine Air Cleaner/Filter for more information.

•	DURAMAX® Diesel Only: Replace fuel filter (or every 750 hours of engine operation, whichever occurs first).

•	Steering system service. (12)

•	Front and rear suspension service. (13)

•	Spring-to-axle U-bolts and shackle bolts service. (15)

•	Exhaust system service (or every 6 months, whichever occurs first). (2) (3) (16)

•	Wheels and tires service. (14)

•	Hydraulic brake service (or every 6 months, whichever occurs first). (6) (36)

•	Parking brake service (or every 6 months, whichever occurs first). (21)

•	Air brake service (or every 6 months, whichever occurs first). (32)

•	Air brake automatic slack adjuster service (or every 500 hours, whichever occurs first). (33)

•	Check air brake relay valve operation and check for leaks (or every month, or every 300 hours, whichever occurs first).

•	Clean air brake application valve (or every 3 months, or every 300 hours, whichever occurs first). Lubricate linkage.

•	Air brake chamber service (or every 2 months, whichever occurs first).(34)

•	Fuel tank, fuel cap and fuel lines service (or every 72 months, whichever occurs first). (2) (26) †

•	Exhaust Gas Recirculation (EGR) system inspection (if equipped) (or every 72 months, whichever occurs first). (2) (27)

•	Thermostatically controlled engine cooling fan service. (3) (19)

•	Shields and underhood insulation service. (3) (4) (20)

•	Air compressor dry element pleated paper air strainer service (or every 2 months or every 800 hours, whichever occurs first).

•	Gasoline Engine Only: Check engine oil life system. If engine oil and filter are changed, reset system. See "Engine Oil (Gasoline Engine)" in the Index. (2) (8)

•	Check fluid levels (or every 3 months, whichever occurs first). (1) (5)

•	Chassis lubrication service (or every 6 months, whichever occurs first). (11)

•	Wheels and tires service. (14)

•	Hydraulic brake service (or every 6 months, whichever occurs first). (6) (36)

•	Parking brake service (or every 6 months, whichever occurs first). (21)

•	Air brake service (or every 6 months, whichever occurs first). (32)

•	Air brake automatic slack adjuster service (or every 500 hours, whichever occurs first). (33)

•	Check air brake relay valve operation and check for leaks (or every month, or every 300 hours, whichever occurs first).

•	Clean air brake application valve (or every 3 months, or every 300 hours, whichever occurs first). Lubricate linkage.

•	Air brake chamber service (or every 2 months, whichever occurs first). (34)

•	Wheel bearings service -- Eaton® axle , oil-filled, (or every 24 months, whichever occurs first). (22) (36)

•	7.8L DURAMAX® Diesel Without Engine Oil Life System Only: Change engine oil and filter (or every 12 months, or every 600 hours of engine operation, whichever occurs first). (2)

•	7.8L DURAMAX® Diesel With Engine Oil Life System Only: Check oil life system (or every 12 months, or every 600 hours of engine operation, whichever occurs first). If engine oil and filter are changed, reset system. See "Engine Oil (DURAMAX® Diesel)" in the Index. (2) (7)

•	Gasoline Engine Only: Check engine oil life system. If engine oil and filter are changed, reset system. See "Engine Oil (Gasoline Engine)" in the Index. (2) (8)

•	6.6L DURAMAX® Diesel Without Engine Oil Life System Only: Change engine oil and filter (or every 12 months, or every 750 hours of engine operation, whichever occurs first). (2)

•	6.6L DURAMAX® Diesel With Engine Oil Life System Only: Check oil life system. If engine oil and filter are changed, reset system. See "Engine Oil (DURAMAX® Diesel)" in the Index. (2) (9)

•	Check fluid levels (or every 3 months, whichever occurs first). (1) (5)

•	Gasoline Engine: Replace engine air cleaner filter. See Engine Air Cleaner/Filter for more information.

•	Diesel Engine: Inspect engine air cleaner filter change indicator. If necessary, replace the filter. If vehicle is driven in dusty/dirty conditions, inspect filter change indicator at every engine oil change. See Engine Air Cleaner/Filter for more information.

•	DURAMAX® Diesel Only: Replace fuel filter (or every 750 hours of engine operation, whichever occurs first).

•	Chassis lubrication service (or every 6 months, whichever occurs first). (11)

•	Cooling system service. Clean the cooling system filler cap with clean water, clean the core, pressure test the cap and the system for proper pressure capability, and inspect condition of cooling and heater hoses and clamps. Replace hoses if cracked, swollen, or damaged.

•	Wheel bearing (grease type) service (or every 24 months, whichever occurs first, and whenever hubs are removed). (22) (36)

•	Replace fuel filter(s) (or every 12 months, whichever occurs first). (2)

•	Steering system service. (12)

•	Front and rear suspension service. (13)

•	Spring-to-axle U-bolts and shackle bolts service. (15)

•	Exhaust system service (or every 6 months, whichever occurs first). (2) (3) (16)

•	Inspect door hinge pins and bushings and replace as necessary.

•	Wheels and tires service. (14)

•	Hydraulic brake service (or every 6 months, whichever occurs first). (6) (36)

•	Parking brake service (or every 6 months, whichever occurs first). (21)

•	Air brake service (or every 6 months, whichever occurs first). (32)

•	Air brake automatic slack adjuster service (or every 500 hours, whichever occurs first). (33)

•	Check air brake relay valve operation and check for leaks (or every month, or every 300 hours, whichever occurs first).

•	Clean air brake application valve (or every 3 months, or every 300 hours, whichever occurs first). Lubricate linkage.

•	Air brake chamber service (or every 2 months, whichever occurs first). (34)

•	Air brake system valve service (or every 3 months, or every 900 hours, whichever occurs first). (37)

•	C600, C700, and C800 Gasoline Engines Only: Engine drive belts service (or every 12 months, whichever occurs first). (17)

•	Thermostatically controlled engine cooling fan service. (3) (19)

•	Shields and underhood insulation service. (3) (4) (20)

•	Rear axle air shift motor service. (10)

•	Air intake system service (or every 24 months, whichever occurs first). (3) (4) (23)

•	Evaporative Control System service, if equipped, (or every 24 months, whichever occurs first). (2) (24) †

•	Air compressor dry element pleated paper air strainer service (or every 2 months or every 800 hours, whichever occurs first).

•	7.8L DURAMAX® Diesel Without Engine Oil Life System Only: Change engine oil and filter (or every 12 months, or every 600 hours of engine operation, whichever occurs first). (2)

•	7.8L DURAMAX® Diesel With Engine Oil Life System Only: Check oil life system (or every 12 months, or every 600 hours of engine operation, whichever occurs first). If engine oil and filter are changed, reset system. See "Engine Oil (DURAMAX® Diesel)" in the Index. (2) (7)

•	Gasoline Engine Only: Check engine oil life system. If engine oil and filter are changed, reset system. See "Engine Oil (Gasoline Engine)" in the Index. (2) (8)

•	Check fluid levels (or every 3 months, whichever occurs first). (1) (5)

•	Chassis lubrication service (or every 6 months, whichever occurs first). (11)

•	Wheels and tires service. (14)

•	Hydraulic brake service (or every 6 months, whichever occurs first). (6) (36)

•	Parking brake service (or every 6 months, whichever occurs first). (21)

•	Air brake service (or every 6 months, whichever occurs first). (32)

•	Air brake automatic slack adjuster service (or every 500 hours, whichever occurs first). (33)

•	Check air brake relay valve operation and check for leaks (or every month, or every 300 hours, whichever occurs first).

•	Clean air brake application valve (or every 3 months, or every 300 hours, whichever occurs first). Lubricate linkage.

•	Air brake chamber service (or every 2 months, whichever occurs first). (34)

•	Diesel Only: Inspect engine drive belt; replace as necessary.

•	Gasoline Engine Only (Vehicles with GVW of 16,000 lbs or less): Spark plug service. (2) (25)

•	Change power steering fluid (or every 36 months, whichever occurs first). (12)

•	Replace power steering reservoir filter element (or every 24 months, whichever occurs first).

•	Except four-wheel drive: Front axle service. (31)

•	Four-wheel drive only: Front axle service. (30)

•	Four-wheel drive only: Transfer case service. (30)

•	Rear axle service -- Eaton®, Rockwell®, Spicer® axles (or every 12 months, whichever occurs first). (30)

•	Exhaust brake service, if equipped. Check for excessive spindle free play and smooth operation. Lubricate ball joint cap.

•	Inspect air compressor discharge port (or every 6 months or every 1,800 hours, whichever occurs first).

•	Manual transmission (ZF 6-speed only) fluid replacement (or every 48 months, whichever occurs first).

•	Trailer brake hand control valve service (or every 12 months, or every 3,600 hours, whichever occurs first). (35)

•	C600, C700, and C800 Gasoline Engines Only: Replace engine drive belts.

•	C400 and C500 Gasoline Engines Only: Engine drive belts service (or every 12 months, whichever occurs first). (17)

•	Cooling system service (or every 60 months since last service, whichever occurs first). (2) (29)

•	Diesel Engine Only: Inspect engine drive belt; replace as necessary.

•	Remove, disassemble, clean, and inspect the air brake trailer supply valve (or every 2 years, or every 7,200 hours, whichever occurs first).

•	Diesel Engine Only: Inspect engine drive belt; replace as necessary.

•	Four-wheel drive only: Front axle service. (30)

•	Four-wheel drive only: Transfer case service. (30)

•	Manual transmission (except ZF 6-speed) fluid replacement (or every 60 months, whichever occurs first).

•	Remove, disassemble, clean, and inspect the air brake air dryer (or every 3 years, or 10,800 hours, whichever occurs first). Replace desiccant.

† = 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. We, however, urge that all recommended maintenance services be performed at the indicated intervals and the maintenance be recorded.

(1) = If your vehicle has an Allison Transmission®, your GM owner manual is supplemented by an Allison Transmission® Operator's Manual. Always refer to these manuals for related maintenance services.

(2) = An Emission Control Service.

(3) = A Noise Emission Control Device.

(4) = Applies to vehicles sold in the United States and is recommended for vehicles sold in Canada.

(5) = Check fluid level in brake master cylinder, power steering pump, axle, transmission, and 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.

(6) = Inspect brake lines and hoses for proper hook-up, binding, leaks, cracks, chafing, etc. Inspect disc brake pads for wear and rotors for surface condition. Inspect caliper assemblies. Check brake pedal for excessive free play or travel (or every 6 months, whichever occurs first) and have serviced if needed. Check brakes more often if driving habits and conditions result in frequent braking.

(7) = This vehicle has the Engine Oil Life System. This system will show you when to change the engine oil and filter -- usually between 3,000 miles (5 000 km) and 12,000 miles (20 000 km) since your last oil change. Under severe conditions, the indicator may come on before 3,000 miles (5 000 km). Never drive your 7.8L diesel engine vehicle more than 12,000 miles (20 000 km), or 12 months, or 600 engine hours, without an oil and filter change.

Remember to reset the Engine Oil Life System whenever the oil is changed. For more information, see Engine Oil Life System .

(8) = This vehicle has the Engine Oil Life System. This system will show you when to change the engine oil and filter -- usually between 3,000 miles (5 000 km) and 7,500 miles (12 000 km) since your last oil change. Under severe conditions, the indicator may come on before 3,000 miles (5 000 km). Never drive your gasoline engine vehicle more than 7,500 miles (12 000 km) or 12 months without an oil and filter change.

Remember to reset the Engine Oil Life System whenever the oil is changed. For more information, see Engine Oil Life System .

(9) = This vehicle has the Engine Oil Life System. This system will show you when to change the engine oil and filter -- usually between 3,000 miles (5 000 km) and 15,000 miles (24 000 km) since your last oil change. Under severe conditions, the indicator may come on before 3,000 miles (5 000 km). Never drive your 6.6L diesel engine vehicle more than 15,000 miles (24 000 km), or 12 months, or 750 engine hours, without an oil and filter change.

Remember to reset the Engine Oil Life System whenever the oil is changed. For more information, see Engine Oil Life System .

(10) = Inspect rear axle air shift motor for fluid leaks. Remove plug to check fluid level. Inspect air lines and hoses for proper hook-up, binding, leaks, etc. Inspect at 1,000 miles (1 600 km) and 22,500 miles (36 000 km) and then every 22,500 miles (36 000 km) thereafter.

(11) = Chassis Lubrication Service: Lubricate all grease fittings in front suspension, front axle, and steering linkage. DO NOT lubricate kingpin bushings with air pressure equipment; instead, use a hand grease gun to ensure complete purge and eliminate sealer cap distortion. Front axle tie rod ends, both upper and lower kingpin fittings, and both steering linkage relay rod ends should be greased with the vehicle loaded on the ground and wheels turned straight ahead, NOT with the vehicle on a hoist. Apply kingpin bushing lubricant to both upper and lower kingpin grease fittings until new lubricant purges from between the upper shim pack and thrust bearing. Lubricate transmission and shift linkage, hood latches and hood hinges, parking brake lever pivot, clevis pins and linkage, disc brake caliper rails, clutch linkage and release bearing (if equipped), bearing pads, propshaft universal joints, brake camshaft bracket, slack adjusters, pedal shaft, clutch cross shaft, clutch pedal springs, and clutch cable bushing at transmission. Lubricate suspension, axle, and steering linkage more often when operating under dusty or muddy conditions and in excessive off-road use. Frequently power-washed vehicles will require more frequent lubrication.

(12) = Check steering system:

(13) = Check front and rear suspension. Look for damaged, loose, or missing parts or parts showing signs of wear or lack of lubrication. Replace parts as needed.

(14) = Adjust tire pressures as indicated on the Gross Vehicle Weight (GVW) Rating label for optimum tire life. See Tires for further details. Check tires for excessive or abnormal wear or damage. Also check for damaged wheels. Replace wheels and/or tires as needed.

(15) = Check spring-to-axle U-bolts and shackle bolts for proper torque. See the service manual for torque sequence and specifications. When parts are replaced, the torque must be checked and adjusted more often during the first 6,000 miles (10 000 km). Check torque at 500 miles (800 km) and 2,000 miles (3 000 km) after first use of parts.

(16) = Check complete exhaust system and cab areas near the exhaust system for broken, damaged, missing, or out-of-position parts. Also inspect for open seams, holes, loose connections, or other conditions which could let exhaust fumes seep into the driver compartment. Needed repairs should be made at once. To help maintain system integrity, replace exhaust pipes whenever a new muffler is put on.

(17) = Check all gasoline engine drive belts for cracks, fraying, and wear. Replace as needed.

(18) = Adjust valve lash. Incorrect valve clearance will result in increased engine noise and reduced engine output.

(19) = With the engine off and below normal operating temperature, check to see that the thermostatically controlled engine cooling fan can be rotated by hand on viscous-operated drives. Replace as needed.

(20) = Check shields and underhood insulation for damage or looseness. Adjust or replace as needed.

(21) = Inspect parking brake drum and linings for wear or cracks and check linkage and adjustment.

(22) = Wheel bearing service:

(23) = Check the air intake system installation to see that gaskets are seated properly and all hose connections, fasteners, and other components are tight. Tighten connections and fasteners or replace parts as required.

(24) = Evaporative Control System Service, if equipped: Check all fuel and vapor lines and hoses for proper connections and correct routing (or every 24 months, whichever occurs first). Replace parts as needed.

(25) = Replace spark plugs. Inspect wires for damage. Check the wire boot and boot heat shield fit at spark plugs and coil. Replace parts as needed.

(26) = Check the fuel tank, fuel cap and fuel lines for damage which could cause leakage. Inspect fuel cap for correct sealing ability and any indications of damage. Check fuel cap gasket for even filler neck imprint. Replace parts as needed.

(27) = Check Exhaust Gas Recirculation (EGR) system as described in the service manual. See Service Publications Ordering Information .

(28) = Inspect Electronic Vacuum Regulator Valve (EVRV) filter for excessive contamination or plugging. If needed, clean filter with solution of soap and water, let dry and install.

(29) = Drain, flush, and refill cooling system. This service can be complex; you should have your dealer perform this service. See Part C: Recommended Fluids and Lubricants for what to use. Inspect hoses. Clean radiator, condenser, pressure cap, and neck. Pressure test cooling system and pressure cap. For Caterpillar® diesel engines, always refer to the Caterpillar® Diesel Engine Operation & Maintenance Manual for coolant recommendations and change intervals.

(30) = Change the lubricant. See Part C: Recommended Fluids and Lubricants .

(31) = Front axle service: Re-pack upper kingpin roller bearing.

(32) = Air brake service:

(33) = Clean and lubricate air brake automatic slack adjuster. Check pushrod travel and auto adjustment operation. Have serviced if needed.

(34) = Air brake chamber service: Check operation, mounting clamps, and air lines and check for leaks.

(35) = Trailer brake hand control valve service: Check operation; lubricate cam and follower.

(36) = Tighten the wheel stud nuts to the specified torque values at 100 miles (160 km). Thereafter, tighten them 1,000 miles (1 600 km) after each time the wheel is removed. See Tightening the Wheel Nuts .

(37) = Inspect and clean any accumulated dirt, gravel, or other foreign objects from the valves and valve boots as needed. Using light oil, lubricate brake pedal to brake application valve linkage components. Check any rubber boots for cracks, holes, or deterioration and replace if necessary.