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Engine Speed Limiter
All engines have electronic engine speed limiting.
The engine limited speeds range between
2,900 and 4,400 rpm depending on engine option
content.
Engine Road Speed Governor
This system controls maximum vehicle speed
automatically and reduces engine power
until vehicle speed gets down to maximum
governed speed.
The default setting for C4500 and C5500 models
up to 19,500 lbs GVWR is 80 to 85 mph
(128 to 136 km/h). Most other models have a
default setting of 75 mph (120 km/h), although
some tire sizes and tread patterns may limit
maximum speed to 55 to 65 mph (86 to 105 km/h).
You may have a label on the headliner of your
vehicle with more information on your engine
road speed governor. See your GM dealer
for assistance with programming your engine
limited speed.
Safety Belt Reminder Light
When the key is turned to RUN or START, a light
will come on for several seconds to remind
people to fasten their safety belts.
The safety belt light will
also come on and stay
on for several seconds.
Safety Belt Reminder Tone
If your vehicle has this feature, when you turn
your key to RUN or START, a tone will sound for
several seconds to remind people to fasten
their safety belts.
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Page 238 of 430

Loading Your Vehicle
It is the responsibility of the Final Stage
manufacturer to install a Certification label on
your vehicle. This label shows how much weight
your vehicle can properly carry. It may also
show the size of the vehicle’s original tires, and
the inflation pressures needed to obtain the
gross weight capacity of your vehicle. This is
called the Gross Vehicle Weight Rating (GVWR).
The tire information could also be shown on a
separate Tire Information label.
The GVWR includes the weight of the vehicle,
all occupants, fuel, and cargo.
The Certification label also tells you the maximum
weight for the front and rear axles, called the
Gross Axle Weight Rating (GAWR). To find out
the actual loads on your front and rear axles,
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 center line.Never exceed the GVWR for your vehicle, or the
GAWR for either the front or rear axle.
And, if you do have a heavy load, spread it out.
{CAUTION:
Do not load your 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 your vehicle can break, and it
can change the way your vehicle handles.
These could cause you to lose control
and crash. Also, overloading can shorten
the life of your vehicle.
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Page 324 of 430

When It Is Time for New Tires
Replace your tires when the tread depth is down
to 1/8 of an inch (3.2 mm) for the front tires,
or 1/16 of an inch (1.6 mm) for a rear tire. Also,
you need a new tire if:
•You can see cord or fabric showing through
the tire’s rubber.
•The tread or sidewall is cracked, cut or
snagged deep enough to show cord or fabric.
•The tire has a bump, bulge or split.
•The tire has a puncture, cut or other damage
that cannot be repaired well because of the
size or location of the damage.
{CAUTION:
Mixing tires could cause you to lose
control while driving. If you mix tires of
different types — like radial and
bias-belted tires — the vehicle may not
handle properly, and you could have a
crash. Be sure to use the same type of
tires all around.When you replace tires, make sure they are the
same size, load range, speed rating and
construction type (bias, bias-belted or radial) as
your original tires.
If your vehicle has four-wheel drive, the axle
differentials, propshafts and transfer case may be
damaged if tires of different sizes, brands or
tread types are installed on the front and rear
axles. That damage would not be covered under
your warranty.
Wheel Alignment and Tire Balance
The wheels on your vehicle were aligned at
the factory to give you the longest tire life and
best overall performance.
Proper front wheel alignment must be maintained
in order to ensure efficient steering, good
directional stability, and prevent abnormal tire
wear. If you notice unusual tire wear or your
vehicle is pulling one way or the other, the
alignment may need to be reset. If you notice your
vehicle vibrating when driving on a smooth
road, your wheels may need to be balanced.
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