Primary Fuel Filter and Water
Separator
Your vehicle may have this
spin-on filter. It is located
on the driver’s side
frame rail.
It has a clear plastic drain bowl at the bottom. Check
the drain bowl occasionally for any water or particles.
To drain the water or to replace the element, follow the
water draining and element replacement procedure
underWater in Fuel on page 5-12.
Secondary Fuel Filter and Heater
Your vehicle may have this fuel filter and fuel heater.
It is mounted on the left side of the engine.
It has a metal drain bowl at the bottom. Occasionally,
check the bowl for any water or particles. To check or
drain the bowl, shut off the engine.
Then push up on the spring-loaded drain valve until
clear fuel is flowing from the valve. The particles or
water will drain out first.
5-79
Secondary Fuel Filter and Water
Separator/Heater
(Caterpillar
®Diesel)
If you have a Caterpillar®
diesel engine, you may
also have this spin-on filter
and fuel separator/heater.
It will be mounted in the
engine compartment on the
driver’s side of the vehicle.
It has a metal drain bowl at the bottom. Occasionally,
check the bowl for any water or particles.To check or drain the bowl, do the following:
•Shut off the engine.
•Push up on the spring loaded drain valve until clear
fuel is flowing from the valve.
The particles or water will drain out first. SeeEngine Oil
(Caterpillar
®Diesel Engine) on page 5-23orEngine
Oil (Gasoline Engine) on page 5-24orEngine Oil
(DURAMAX
®Diesel Engine) on page 5-28orEngine Oil
(Isuzu Diesel Engine) on page 5-32for proper disposal
procedures.
5-80
Part GM Part Number ACDelco®Part Number
Fuel Filter
6.6L V8 97385488 TP1298A
7.2L L6 — 1R-0751††
Isuzu 6H 98026037 —
8.1L V8 (C4/C5 with NG6/NK1 or U-Haul) 21998364 —
8.1L V8 (C4/C5 with all other fuel tanks) 10376257 —
8.1L V8 (All C6/C7/C8) 10370247 —
Power Steering Fluid Filter 88892858 —
Secondary Fuel Filter
6.6L V8 — —
7.2L L6 (NWB) 15618921 —
Isuzu 6H 25014274 TP915D
Isuzu 6H (KUK) 88983117 TP1519
8.1L V8 (K28 and standard U-Haul) 25014476 TP1247
Spark Plugs
6.6L V8 — —
7.2L L6 — —
Isuzu 6H — —
8.1L V8 12578277 41-983
1Optional air filter (GM Part No. 88937548 AC Delco No. A2035C) for C6/C7/C8 Models. Fits inside standard size
filter (GM Part No. 88937525 AC Delco No. A2031C) listed previously.
†Racor part number.
††Caterpillar
®part number.
See the Allison Transmission®Operator’s Manual in your vehicle for external filter part numbers and information.
5-116
❑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)
15,000 Miles (24 000 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)
❑DURAMAX
®/Isuzu 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) (39)
❑DURAMAX
®/Isuzu 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 5-39
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. SeeEngine Air
Cleaner/Filter on page 5-39for 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).
6-6
❑Evaporative Control System service, if equipped, (or
every 24 months, whichever occurs first).(2) (24) †
❑Rear axle air shift motor service.(10)
24,000 Miles (40 000 km)
❑Lubricate U-joints (or every 6 months, whichever
occurs first).
30,000 Miles (48 000 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)
❑DURAMAX
®/Isuzu 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) (39)
❑DURAMAX
®/Isuzu 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: 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 5-39for 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 on page 5-39for 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)
❑Check restraint system.(40)
❑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)
6-8
45,000 Miles (72 000 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)
❑DURAMAX
®/Isuzu 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) (39)
❑DURAMAX
®/Isuzu 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 5-39for
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 on page 5-39for 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)
❑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.
❑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)
6-10
❑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)
60,000 Miles (96 000 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)
❑DURAMAX
®/Isuzu 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) (39)
❑DURAMAX
®/Isuzu 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)
❑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 5-39for 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 on page 5-39for 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.
❑Check restraint system.(40)
❑Steering system service.(12)
❑Front and rear suspension service.(13)
❑Spring-to-axle U-bolts and shackle bolts service.(15)
6-12
❑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 on page 5-39for 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)
❑Air compressor dry element pleated paper air strainer
service (or every 2 months, or every 800 hours,
whichever occurs first).
❑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)
❑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).
6-15