ApplicationCapacities
English Metric
Fuel Capacity – C4/C5 Models
Standard (Mid-Mounted) 25 gal 94.6 L
Optional
1(Dual-Tank) (Mid-Mounted) 40 gal 151.4 L
Optional (Mid-Mounted) 32 gal 121.1 L
Optional (Side-Mounted) 35 gal 132.5 L
Optional (Mid-Mounted) 40 gal 151.4 L
Optional (Mid-Mounted) 60 gal 227.1 L
Optional (Mid-Mounted) 80 gal 302.8 L
1One 25-gallon (94.6 L) tank and one 15-gallon (56.8 L) tank
Fuel Capacity – C6/C7/C8 Models
Optional 35 gal 132.4 L
Standard 50 gal 189.2 L
Optional 50 gal 189.2 L
Optional
1(Dual Tanks) 70 gal 264.8 L
Optional
2(Dual Tanks) 75 gal 283.8 L
Optional
3(Dual Tanks) 100 gal 378.5 L
1Two 35-gallon (132.4 L) tanks2One 25-gallon (94.6 L) tank and one 50-gallon (189.2 L) tank3Two 50-gallon (189.2 L) tanks
5-111
ApplicationCapacities
English Metric
Transmission Fluid, Manual
ES052-7, ES066-7 22.0 pt 10.4 L
FS5205A 12.5 pt 5.9 L
FSO8406, FS6305A, FS6305B, FS6406, FS5406A 19.5 pt 9.2 L
FS4205A, FS4205B 11.5 pt 5.4 L
RT6609 12.0 pt 5.7 L
RT8709 26.0 pt 12.3 L
RT8908LL 28.0 pt 13.2 L
All capacities are approximate. When adding, be sure to fill to the approximate level, as recommended in this
manual. Recheck the fluid level after filling.
Engine Speci cations
Engine RPO Type
6.6L V8 DURAMAX
®LMM Common Rail Fuel System
7.2L L6 Caterpillar
®C7 LF6Hydraulic/Electronic Unit Injector
Fuel System
7.8L L6
Isuzu 6HLF8 Common Rail Fuel System
8.1L V8 VORTEC™ L18Single Port Fuel Injector Fuel
System
5-114
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
Maintenance Schedule......................................6-2
Introduction...................................................6-2
Maintenance Requirements..............................6-2
Your Vehicle and the Environment....................6-2
How This Section is Organized.........................6-3
Part A: Scheduled Maintenance Services...........6-4
Using the Maintenance Schedule......................6-4
Scheduled Maintenance Supplements................6-4Scheduled Maintenance...................................6-5
Part B: Owner Checks and Services................6-26
At Each Fuel Fill..........................................6-26
At Least Twice a Year...................................6-27
At Least Once a Year...................................6-30
Part C: Recommended Fluids and Lubricants. . . .6-31
Part D: Maintenance Record..........................6-33
Section 6 Maintenance Schedule
6-1
Part A: Scheduled Maintenance
Services
In this part are scheduled maintenance services which
are to be performed at the mileage intervals specified.
Using the Maintenance Schedule
We want to help keep your vehicle in good working
condition. But we do not know exactly how you will drive
it. You might drive very short distances only a few times
a week. Or you might drive long distances all the
time in very hot, dusty weather. You might use your
vehicle in making deliveries or in many other ways.
Because of all the different ways people use their
vehicles, maintenance needs vary. You might need
more frequent checks and replacements. So please read
the following and note how you drive. If you have any
questions on how to keep your vehicle in good condition,
see your dealer/retailer.
This part tells you the maintenance services you should
have done and when to schedule them.
When you go to your dealer/retailer for your service
needs, you will know that trained and supported service
people will perform the work using genuine parts.The proper fluids and lubricants to use are listed in
Part C. Make sure whoever services your vehicle uses
these. All parts should be replaced and all necessary
repairs done before you or anyone else drives the
vehicle.
This schedule is for vehicles that:
•carry passengers and cargo within recommended
limits. You will find limits on your vehicle’s
Certification or Tire Information label. SeeLoading
Your Vehicle on page 4-21.
•are driven on reasonable road surfaces within legal
driving limits.
•use the recommended fuel. SeeGasoline Octane
on page 5-7for gasoline engine vehicles orWhat
Fuel to Use on page 5-9for diesel engine vehicles.
Scheduled Maintenance
Supplements
If your vehicle has a Caterpillar®diesel engine, your
owner manual is supplemented by the Caterpillar®
Diesel Engine Operation & Maintenance Manual. If your
vehicle has an Allison Transmission®, your owner
manual is supplemented by an Allison Transmission®
Operator’s Manual. Always refer to these manuals
for related maintenance services.
6-4
❑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