
Item Description Total
AVehicle Capacity Weight
for Example 3=1,000 lbs (453 kg)
BSubtract Occupant
Weight 200 lbs
(91 kg)×5=1000 lbs (453 kg)
CAvailable Cargo
Weight=0 lbs (0 kg)
Refer to your vehicle’s tire and loading information label
for speci c information about your vehicle’s capacity
weight and seating positions. The combined weight of
the driver, passengers and cargo should never
exceed your vehicle’s capacity weight.
Certi cation/Tire Label
A vehicle speci c Certi cation/Tire label is found on the
rear edge of the driver’s door. The label shows the
size of your vehicle’s original tires and the in ation
pressures needed to obtain the gross weight capacity
of your vehicle. This is called Gross Vehicle Weight
Rating (GVWR). The GVWR includes the weight of the
vehicle, all occupants, fuel and cargo. Example 3
4-53

Q:What is front axle reserve capacity, and how do
I calculate it?
A:Front axle reserve capacity is the difference
between your front gross axle weight rating (GAWR)
and the front axle weight of your vehicle with full
fuel and passengers. Basically, it is the amount of
weight you can add to your front axle before
reaching your front GAWR.
The front axle reserve capacity for your vehicle can be
found in the lower right corner of the Certi cation/Tire
label, as shown.In order to calculate the amount of weight any front
accessory, such as a snow plow, is adding to the front
axle, use the following formula:
(W x (A + W.B.)) /W.B.= Weight the accessory is adding
to the front axle.
Where:
W = Weight of added accessory
A = Distance that the accessory is in front of the
front axle
W.B. = Vehicle Wheelbase United States
Canada
4-58

Q:What is total vehicle reserve capacity?
A:This is the difference between your GVWR and the
weight of your truck with full fuel and passengers.
It is the amount of weight you can add to your
vehicle before reaching your GVWR. Keep in mind
that reserve capacity numbers are intended as
a guide when selecting the amount of equipment or
cargo your truck can carry. If you are unsure of
your vehicle’s front, rear, or total weight, go
to a weigh station and weigh your vehicle.
Your dealer can also help you with this.
The total vehicle reserve capacity for your vehicle
can be found in the lower right corner of the
Certi cation/Tire label as shown previously.
See your dealer for additional advice and information
about using a snow plow on your vehicle. Also,
seeLoading Your Vehicle on page 4-50.
Emergency Roof Lamp Provisions
Vehicles with the RPO VYU snow plow prep package
also have an emergency roof lamp provision package,
RPO TRW. Wiring for the emergency roof lamp is
provided in the B-pillar as shown. SeeAuxiliary Roof
Mounted Lamp on page 3-17for switch location.
A. Body Side Inner Panel
B. Emergency Roof Lamp Harness
4-60

If your vehicle was built with trailering options, as many
are, it’s ready for heavier trailers. But trailering is different
than just driving your vehicle by itself. Trailering means
changes in acceleration, braking, handling, durability and
fuel economy. Successful, safe trailering takes correct
equipment, and it has to be used properly.
That’s the reason for this part. In it are many time-tested,
important trailering tips and safety rules. Many of
these are important for your safety and that of your
passengers. So please read this section carefully before
you pull a trailer.
If You Do Decide To Pull A Trailer
Notice:Pulling a fth-wheel trailer with a vehicle
that is equipped with the SS trim package could
damage the vehicle. Do not pull a fth-wheel trailer
with a vehicle equipped with the SS trim package.
If you do, here are some important points:
There are many different laws, including speed limit
restrictions, having to do with trailering. Make sure
your rig will be legal, not only where you live
but also where you’ll be driving. A good source for
this information can be state or provincial police.
Consider using a sway control. See “Hitches” later
in this section.
Don’t tow a trailer at all during the rst 500 miles
(800 km) your new vehicle is driven. Your engine,
axle or other parts could be damaged.
Then, during the rst 500 miles (800 km) that you
tow a trailer, don’t drive over 50 mph (80 km/h)
and don’t make starts at full throttle. This helps your
engine and other parts of your vehicle wear in at
the heavier loads.
If you have an automatic transmission, you can
tow in DRIVE (D). You may want to shift the
transmission to THIRD (3) or, if necessary, a lower
gear selection if the transmission shifts too often,
such as under heavy loads and/or hilly conditions.
If you have a manual transmission and you are
towing a trailer, it’s better not to use the highest
gear. SeeTow/Haul Mode Light on page 3-48.
Three important considerations have to do with weight:
The weight of the trailer
The weight of the trailer tongue
The weight on your vehicle’s tires
4-70

Tow/Haul Mode
Tow/Haul is a feature on automatic transmission
equipped vehicles that assists when pulling a heavy
trailer or a large or heavy load. Tow/Haul mode adjusts
the transmission’s shift pattern to reduce shift cycling
(rapid up and downshifts/gear hunting), providing
increased performance, vehicle control, and transmission
cooling when towing or hauling heavy loads.
Automatic transmission equipped vehicles are provided
with a button at the end of the shift lever which when
pressed enables Tow/Haul. When the button is pressed,
a light on the instrument panel will illuminate to
indicate that Tow/Haul has been selected. Tow/Haul
may be turned off by pressing the button again, at which
time the indicator light on the instrument panel will
turn off. The vehicle will automatically turn off Tow/Haul
every time it is started.Tow/Haul is designed to be most effective when the
vehicle and trailer combined weight is at least 75% of
the vehicle’s Gross Combined Weight Rating (GCWR).
See “Weight of the Trailer” later in the section.
Tow/Haul is most useful under the following driving
conditions:
When pulling a heavy trailer or a large or heavy
load through rolling terrain.
When pulling a heavy trailer or a large or heavy
load in stop and go traffic.
When pulling a heavy trailer or a large or heavy
load in busy parking lots where improved low
speed control of the vehicle is desired.
Operating the vehicle in Tow/Haul when lightly loaded
or with no trailer at all will not cause damage. However,
there is no bene t to the selection of Tow/Haul when
the vehicle is unloaded. Such a selection when unloaded
may result in unpleasant engine and transmission
driving characteristics and reduced fuel economy.
Tow/Haul is recommended only when pulling a heavy
trailer or a large or heavy load.
4-71

Service............................................................5-4
Doing Your Own Service Work.........................5-4
Adding Equipment to the Outside of
Your Vehicle..............................................5-5
Fuel................................................................5-5
Gasoline Octane............................................5-6
Gasoline Speci cations....................................5-6
California Fuel...............................................5-6
Additives.......................................................5-7
Fuel E85 (85% Ethanol)..................................5-8
Fuels in Foreign Countries...............................5-9
Filling the Tank............................................5-10
Filling a Portable Fuel Container.....................5-12
Checking Things Under the Hood....................5-12
Hood Release..............................................5-13
Engine Compartment Overview.......................5-14
Engine Oil (Gasoline Engine)..........................5-20
Engine Oil Life System
(Gasoline Engine)......................................5-23
Engine Air Cleaner/Filter................................5-25
Automatic Transmission Fluid
(Except Allison Transmission
®) ....................5-27
Automatic Transmission Fluid
(Allison Transmission
®) ...............................5-30Manual Transmission Fluid.............................5-33
Hydraulic Clutch...........................................5-34
Engine Coolant.............................................5-35
Coolant Surge Tank Pressure Cap..................5-38
Engine Overheating.......................................5-38
Overheated Engine Protection Operating Mode
(V8 Engines Only)......................................5-40
Cooling System............................................5-40
Engine Fan Noise.........................................5-45
Power Steering Fluid.....................................5-46
Windshield Washer Fluid................................5-47
Brakes........................................................5-48
Battery........................................................5-51
Jump Starting...............................................5-52
All-Wheel Drive..............................................5-57
Rear Axle.......................................................5-58
Four-Wheel Drive............................................5-59
Front Axle......................................................5-60
Noise Control System.....................................5-61
Tampering with Noise Control System
Prohibited.................................................5-61
Section 5 Service and Appearance Care
5-1

If you want to do some of your own service work, you
will want to use the proper service manual. It tells
you much more about how to service your vehicle than
this manual can. To order the proper service manual,
seeService Publications Ordering Information on
page 7-11.
Your vehicle has an airbag system. Before attempting
to do your own service work, seeServicing Your
Airbag-Equipped Vehicle on page 1-78.
You should keep a record with all parts receipts and list
the mileage and the date of any service work you
perform. SeeMaintenance Record on page 6-18.
Adding Equipment to the Outside of
Your Vehicle
Things you might add to the outside of your vehicle
can affect the air ow around it. This may cause
wind noise and affect windshield washer performance.
Check with your dealer before adding equipment to
the outside of your vehicle.
Fuel
If your vehicle has a diesel engine, see “Diesel Fuel
Requirements and Fuel System” in the DURAMAX®
Diesel Supplement.
For vehicles with gasoline engines, please read this.
Gasoline
The 8th digit of your vehicle identi cation number (VIN)
shows the code letter or number that identi es your
engine. You will nd the VIN at the top left of the
instrument panel. SeeVehicle Identi cation Number
(VIN) on page 5-122.
If your vehicle has the 5.3L V8 engine (VIN Code Z
only), you may use either regular unleaded gasoline or
ethanol fuel containing up to 85% ethanol (E-85);
also seeFuel E85 (85% Ethanol) on page 5-8.Inall
other engines, use only regular unleaded gasoline.
5-5

Gasoline Octane
For all except vehicles with the 6.0L V8 (VIN Code N)
engine, use regular unleaded gasoline with a posted
octane of 87 or higher. If the octane is less than 87, you
may get a heavy knocking noise when you drive. If this
occurs, use a gasoline rated at 87 octane or higher as
soon as possible. Otherwise, you might damage your
engine. A little pinging noise when you accelerate or drive
uphill is considered normal. This does not indicate a
problem exists or that a higher-octane fuel is necessary.
If you are using 87 octane or higher-octane fuel and hear
heavy knocking, your engine needs service.
If you have the 6.0L V8 (VIN Code N) engine, use
premium unleaded gasoline with a posted octane of
91 or higher for best performance. You may also use
middle grade or regular unleaded gasoline rated at
87 octane or higher, but your vehicle’s acceleration may
be slightly reduced. If the octane is less than 87, you may
get a heavy knocking noise when you drive. If this occurs,
use gasoline rated at 87 octane or higher as soon as
possible. Otherwise, you might damage your engine.
Gasoline Speci cations
It is recommended that gasoline meet speci cations
which were developed by automobile manufacturers
around the world and contained in the World-Wide Fuel
Charter which is available from the Alliance of Automobile
Manufacturers at www.autoalliance.org/fuel_charter.htm.
Gasoline meeting these speci cations could provide
improved driveability and emission control system
performance compared to other gasoline.
California Fuel
If your vehicle is certi ed to meet California Emissions
Standards, it is designed to operate on fuels that meet
California speci cations. See the underhood emission
control label. If this fuel is not available in states adopting
California emissions standards, your vehicle will operate
satisfactorily on fuels meeting federal speci cations, but
emission control system performance may be affected.
The malfunction indicator lamp may turn on and your
vehicle may fail a smog-check test. SeeMalfunction
Indicator Lamp on page 3-44. If this occurs, return to your
authorized GM dealer for diagnosis. If it is determined
that the condition is caused by the type of fuel used,
repairs may not be covered by your warranty.
5-6