
❑Isuzu 6H 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
®/Isuzu 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. SeeEngine Air
Cleaner/Filter on page 280for 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. SeeEngine Air Cleaner/Filter
on page 280for more information.
❑DURAMAX
®/Isuzu 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)
❑Wheel bearing (grease type) service (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)
374

❑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)
❑Gasoline Engine: Air compressor remote
mounted air filter dry element pleated paper
air strainer service (or every 6 months or
every 1800 hours, whichever occurs first).67,500 Miles (108 000 km)
❑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.
❑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)
375

❑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
®/Isuzu 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. SeeEngine
Air Cleaner/Filter on page 280for 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. SeeEngine Air Cleaner/Filter
on page 280for more information.
❑DURAMAX
®/Isuzu 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)
377

84,000 Miles (140 000 km)
❑Isuzu 6H 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)
❑Isuzu 6H 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
®/Isuzu Diesel)” in the Index.(2) (7)
90,000 Miles (144 000 km)
❑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
®/Isuzu
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. SeeEngine Air Cleaner/Filter on
page 280for 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. SeeEngine Air Cleaner/Filter
on page 280for more information.
❑DURAMAX
®/Isuzu 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)
379

❑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.
❑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.
❑Wheel bearing (grease type) service (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)
❑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)
380

(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,
seeEngine Oil Life System (Gasoline Engine)
on page 276orEngine Oil Life System
(DURAMAX
®Diesel) on page 278orEngine
Oil Life System (Caterpillar®Diesel Engine)
on page 279.(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,
seeEngine Oil Life System (Gasoline Engine)
on page 276orEngine Oil Life System
(DURAMAX®Diesel) on page 278orEngine
Oil Life System (Caterpillar®Diesel Engine)
on page 279.
(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.
385

(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:
•Look for damaged, loose, or missing parts.
Inspect the steering linkage relay rod and
tie rod ends for looseness or lack of lubricant.
Also look for parts showing signs of wear
or lack of lubrication. Replace parts as
needed. Also check steering gear mounting
bolts, pitman arm nut, gear housing upper
cover and side cover attaching bolts, steering
column mounting bolts and cardan joint
clamp bolts; tighten if necessary. See the
service manual.
•Inspect power steering hoses, tubes, and
fittings for leaks. Hoses and lines must not
be twisted, kinked, or tightly bent. Make sure
clips, clamps, supporting tubes, and hoses
are in place and properly secured.
•Check steering gear for leakage around
pitman shaft and housing. If leakage is evident
(lubricant oozing out, not just oily film), leak
should be corrected immediately.
386

(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
Certification or Tire Information label for optimum
tire life. SeeTires on page 321for 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.
387