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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 Reminders
Safety Belt Reminder Light
When the engine is started, 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 the engine is
started, a tone will sound for several seconds to remind
people to fasten their safety belts.
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Page 178 of 376

Your Driving, the Road, and
the Vehicle
Driving for Better Fuel Economy
Driving habits can affect fuel mileage. Here are some
driving tips to get the best fuel economy possible.
•Avoid fast starts and accelerate smoothly.
•Brake gradually and avoid abrupt stops.
•Avoid idling the engine for long periods of time.
•When road and weather conditions are appropriate,
use cruise control, if equipped.
•Always follow posted speed limits or drive more
slowly when conditions require.
•Keep vehicle tires properly inflated.
•Combine several trips into a single trip.
•Replace the vehicle’s tires with the same TPC Spec
number molded into the tire’s sidewall near the size.
•Follow recommended scheduled maintenance.
Defensive Driving
Defensive driving means “always expect the
unexpected.” The first step in driving defensively is to
wear your safety belt — SeeSafety Belts: They Are for
Everyone on page 1-11.
{CAUTION:
Assume that other road users (pedestrians,
bicyclists, and other drivers) are going to be
careless and make mistakes. Anticipate what they
might do and be ready. In addition:
•Allow enough following distance between you
and the driver in front of you.
•Focus on the task of driving.
Driver distraction can cause collisions resulting in
injury or possible death. These simple defensive
driving techniques could save your life.
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Page 196 of 376

Tow Hooks
{CAUTION:
These hooks, when used, are under a lot of force.
Always pull the vehicle straight out. Never pull on
the hooks at a sideways angle. The hooks could
break off and you or others could be injured from
the chain or cable snapping back.
Notice:Never use tow hooks to tow the vehicle.
Your vehicle could be damaged and it would not be
covered by warranty.
If your vehicle has tow hooks, the hooks are at the front
and, on some models, the rear of the vehicle. You
may need to use them if you are stuck off-road and need
to be pulled to some place where you can continue
driving.
Loading the 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.
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Page 280 of 376

Wheel Loading
Wheels are stamped with a maximum load and cold
inflation rating. Be sure you do not exceed these limits.
Dual Tire Operation
When the vehicle is new, check the wheel nut tightness
on all wheels with a torque wrench after your first
100 miles (160 km) and then 1,000 miles (1 600 km) after
that. Whenever a wheel, wheel bolt or wheel nut is
removed or serviced, repeat the 100 miles (160 km), and
then 1,000 mile (1 600 km) wheel nut tightness check.
SeeTightening the Wheel Nuts on page 5-80for wheel
nut tightening information and proper torque values.
{CAUTION:
If you operate your vehicle with a tire that is badly
underinflated, the tire can overheat. An overheated
tire can lose air suddenly or catch fire. You or
others could be injured. Be sure all tires (including
the spare, if any) are properly inflated.
SeeTires on page 5-76andInflation - Tire Pressure on
page 5-77for more information on proper tire inflation.
When It Is Time for New Tires
Various factors, such as maintenance, temperatures,
driving speeds, vehicle loading, and road conditions,
influence when you need 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.
The rubber in tires degrades over time, even if they are
not being used. This is also true for the spare tire, if your
vehicle has one. Multiple conditions affect how fast this
aging takes place, including temperatures, loading
conditions, and inflation pressure maintenance. With
proper care and maintenance tires will typically wear out
before they degrade due to age. If you are unsure about
the need to replace your tires as they get older, consult
the tire manufacturer for more information.
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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.
Buying New Tires
GM has developed and matched specific tires for your
vehicle. If you need replacement tires, GM strongly
recommends that you get tires that are the same size,
brand, load range, speed rating, and construction type
(radial and bias-belted tires) as your vehicle’s original
tires. This way, your vehicle will continue to have tires
that are designed to give the same performance and
vehicle safety, during normal use, as the original tires.
GM recommends replacing tires in sets of six or eight as
applicable. This is because uniform tread depth on all
tires will help keep your vehicle performing most like it did
when the tires were new. Replacing less than a full set of
tires can affect the braking and handling performance of
your vehicle.
{CAUTION:
Mixing tires could cause you to lose control
while driving. If you mix tires of different
sizes, brands, or types (radial and bias-belted
tires) the vehicle may not handle properly,
and you could have a crash. Using tires of
different sizes, brands, or types may also
cause damage to your vehicle. Be sure to
use the correct size, brand, and type of tires
on your vehicle’s wheels.
{CAUTION:
If you use bias-ply tires on the vehicle, the
wheel rim flanges could develop cracks after
many miles of driving. A tire and/or wheel
could fail suddenly, causing a crash. Use
only radial-ply tires with the wheels on the
vehicle.
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