Page 402 of 630

The Certification/Tire label also tells you the
maximum weights for the front and rear axles,
called Gross Axle Weight Rating (GAWR). To find
out the actual loads on your front and rear axles,
you need to go to a weigh station and weigh your
vehicle. Your dealer can help you with this. Be
sure to spread out your load equally on both sides
of the centerline.
Never exceed the GVWR for your vehicle, or the
GAWR for either the front or rear axle.
The Certification/Tire label also contains important
information about your Front Axle Reserve
Capacity. See“What is front axle reserve capacity,
and how do I calculate it?” underAdding a Snow
Plow or Similar Equipment
on page 5‑36.
{WARNING:
In the case of a sudden stop or collision,
things carried in the bed of your truck could
shift forward and come into the passenger
area, injuring you and others. If you put
things in the bed of your truck, you should
make sure they are properly secured.
{WARNING:
Do not load the vehicle any heavier than
the Gross Vehicle Weight Rating (GVWR),
or either the maximum front or rear Gross
Axle Weight Rating (GAWR). If you do, parts
on the vehicle can break, and it can change
the way the vehicle handles. These could
cause you to lose control and crash.
Also, overloading can shorten the life
of the vehicle.
Notice :Overloading the vehicle may cause
damage. Repairs would not be covered by the
vehicle warranty. Do not overload the vehicle.
Using heavier suspension components to get
added durability might not change your weight
ratings. Ask your dealer to help you load your
vehicle the right way.
If you put things inside your vehicle —like
suitcases, tools, packages, or anything
else —they go as fast as the vehicle goes.
If you have to stop or turn quickly, or if there
is a crash, they will keep going.
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Page 535 of 630

Tire Chains
{WARNING:
If your vehicle has dual wheels or P265/65R18,
P275/55R20 or LT265/70R17 size tires, do not
use tire chains. They can damage your vehicle
because there is not enough clearance. Tire
chains used on a vehicle without the proper
amount of clearance can cause damage to the
brakes, suspension, or other vehicle parts. The
area damaged by the tire chains could cause you
to lose control of your vehicle and you or others
may be injured in a crash.
Use another type of traction device only if its
manufacturer recommends it for use on your
vehicle and tire size combination and road
conditions. Follow that manufacturer's
instructions. To help avoid damage to your
vehicle, drive slowly, readjust, or remove the
device if it is contacting your vehicle, and do not
spin your vehicle's wheels.
If you do find traction devices that will fit, install
them on the rear tires.Notice:
If your vehicle does not have dual
wheels and has a tire size other than P265/65R18,
P275/55R20 or LT265/70R17, use tire chains only
where legal and only when you must. Use chains
that are the proper size for your tires. Install them
on the tires of the rear axle. Do not use chains on
the tires of the front axle. Tighten them as tightly as
possible with the ends securely fastened. Drive
slowly and follow the chain manufacturer's
instructions. If you can hear the chains contacting
your vehicle, stop and retighten them. If the contact
continues, slow down until it stops. Driving too fast
or spinning the wheels with chains on will damage
your vehicle.
If a Tire Goes Flat
It is unusual for a tire to blowout while you are driving,
especially if you maintain your vehicle's tires properly.
If air goes out of a tire, it is much more likely to leak out
slowly. But if you should ever have a blowout, here are
a few tips about what to expect and what to do:
If a front tire fails, the flat tire creates a drag that pulls
the vehicle toward that side. Take your foot off the
accelerator pedal and grip the steering wheel firmly.
Steer to maintain lane position, and then gently brake to
a stop well out of the traffic lane.
6-89
Page 578 of 630

When the Change Engine Oil Soon message
displays, certain services, checks, and inspections are
required. The services described for MaintenanceI
should be performed at every engine oil change.
The services described for Maintenance IIshould be
performed when:
.Maintenance Iwas performed the last time the
engine oil was changed.
.It has been 10 months or more since the Change
Engine Oil Soon message has displayed or since
the last service.
Maintenance I
.Change engine oil and filter. See Engine Oilon
page 6‑18. An Emission Control Service.
.Engine coolant level check. See Engine Coolanton page 6‑31.
.Windshield washer fluid level check. See
Windshield Washer Fluid on page 6‑38.
.Tire inflation check. SeeInflation - Tire Pressureon page 6‑72.
.Tire wear inspection. See Tire Inspection and
Rotation on page 6‑80.
.Rotate tires. See Tire Inspection and Rotationon
page 6‑80.
.Fluids visual leak check (or every 12 months,
whichever occurs first). A leak in any system
must be repaired and the fluid level checked.
.Engine air cleaner filter inspection (vehicles
driven in dusty conditions only). See Engine Air
Cleaner/Filter on page 6‑21.
.Brake system inspection (or every 12 months,
whichever occurs first).
.For vehicles with Allison Transmission®only:
At the first engine oil change only, replace external
transmission filter.
Maintenance II
.Perform all services described in Maintenance I.
.Steering and suspension inspection. Visual
inspection for damaged, loose, or missing parts or
signs of wear.
.Lubricate the front suspension, steering linkage,
and parking brake cable guides. Control arm
ball joints on 2500/3500 series vehicles require
lubrication but should not be lubricated unless their
temperature is−12°C (10°F) or higher, or they
could be damaged. Control arm ball joints on
1500 series vehicles are maintenance‐free.
Vehicles used under severe commercial operating
conditions require lubrication on a regular basis
every 5 000 km/3,000 miles.
7-4
Page 583 of 630
Scheduled Maintenance
ServiceMaintenanceIMaintenance II
Change engine oil and filter. Reset oil life system. ••
Engine coolant level check. ••
Windshield washer fluid level check. ••
Tire inflation pressures check. ••
Tire wear inspection. ••
Rotate tires. ••
Fluids visual leak check. ••
Engine air cleaner filter inspection (vehicles driven in dusty conditions only). ••
Brake system inspection. ••
Allison Transmission
®only: External transmission filter replacement (at the first
maintenance service performed on the vehicle only).
Steering and suspension inspection. •
7-9
Page 610 of 630

Reporting Safety Defects to the
Canadian Government
If you live in Canada, and you believe that your
vehicle has a safety defect, notify Transport Canada
immediately, in addition to notifying General Motors of
Canada Limited. Call them at 1-800-333-0510 or
write to:Transport Canada
Road Safety Branch
2780 Sheffield Road
Ottawa, Ontario K1B 3V9
Reporting Safety Defects to
General Motors
In addition to notifying NHTSA (or Transport Canada) in
a situation like this, please notify General Motors.
Call 1-800-GMC-8782 (1-800-462-8782), or write:GMC Customer Assistance Center
P.O. Box 33172
Detroit, MI 48232-5172 In Canada, call 1-800-263-3777 (English) or
1-800-263-7854 (French), or write:
General Motors of Canada Limited
Customer Communication Centre, CA1-163-005
1908 Colonel Sam Drive
Oshawa, Ontario L1H 8P7
Service Publications Ordering
Information
Service Manuals
Service Manuals have the diagnosis and repair
information on engines, transmission, axle suspension,
brakes, electrical, steering, body, etc.
Service Bulletins
Service Bulletins give additional technical service
information needed to knowledgeably service General
Motors cars and trucks. Each bulletin contains
instructions to assist in the diagnosis and service of
your vehicle.
8-16