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2-14
New Vehicle ªBreak-Inº
NOTICE:
Your vehicle doesn't need an elaborate
ªbreak
-in.º But it will perform better in the long
run if you follow these guidelines:
Let your engine warm up before you
operate your vehicle under load.
Keep your speed at 55 mph (88 km/h) or
less for the first 500 miles (805 km).
Don't drive at any one speed
-- fast or
slow
-- for the first 500 miles (805 km).
Don't make full
-throttle starts.
NOTICE: (Continued)
NOTICE: (Continued)
Avoid making hard stops for the first
200 miles (322 km) or so. During this time
your new brake linings aren't yet broken
in. Hard stops with new linings can mean
premature wear and earlier replacement.
Follow this breaking
-in guideline every
time you get new brake linings.
Use the lowest gear you can when you start
a loaded vehicle in motion and when going
up hills to avoid overloading the engine.
Check and adjust engine and transmission
fluid levels often and be sure tires are
properly inflated for the load you're
carrying.
If you have a Caterpillar
diesel engine, see
the Caterpillar Diesel Engine Operation
& Maintenance Manual.
Page 217 of 386
4-24
Hill and Mountain Roads
Driving on steep hills or mountains is different from
driving in flat or rolling terrain.Here are some tips that can make your drive through
steep country safer:
Keep the vehicle in good shape. Check all fluid
levels and also the brakes, tires, cooling system and
transmission. These parts can work hard on
mountain roads.
Know how to go down hills. The most important
thing to know is this: let your engine do some of the
slowing down. Shift to a lower gear when you go
down a steep or long hill.
CAUTION:
If you don't shift down, your brakes could get
so hot that they wouldn't work well. You would
then have poor braking or even none going
down a hill. You could crash. Shift down to let
your engine assist your brakes on a steep
downhill slope.
Page 223 of 386
4-30
If you have a diesel engine, you may have to run it at a
higher speed to get enough heat. Then, shut the engine
off and close the window almost all the way to preserve
the heat. Start the engine again and repeat this only
when you feel really uncomfortable from the cold. But
do it as little as possible. Preserve the fuel as long as you
can. To help keep warm, you can get out of the vehicle
and do some fairly vigorous exercises every half hour or
so until help comes.Loading Your Vehicle
There is a GVW Rating label on your vehicle that shows
how much weight it may properly carry. It also shows
the size of your 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).
Page 226 of 386
5-
5-1
Section 5 Problems on the Road
Here you'll find what to do about some problems that can occur on the road.
5
-2 Hazard Warning Flashers
5
-3 Other Warning Devices
5
-3 Jump Starting
5
-10 Towing Your Vehicle
5
-17 Engine Overheating5
-20 Cooling System
5
-26 Engine Fan Noise
5
-26 If a Tire Goes Flat
5
-27 Changing a Flat Tire
5
-28 If You're Stuck: In Sand, Mud, Ice or Snow
Page 251 of 386

5-26
Engine Fan Noise
Your vehicle has a clutched engine cooling fan. When
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions, the clutch is not fully engaged. This
improves fuel economy and reduces fan noise. Under
heavy vehicle loading, trailer towing and/or high outside
temperatures, the fan speed increases when the clutch
engages. So you may hear an increase in fan noise.
This is normal and should not be mistaken as the
transmission slipping or making extra shifts. It is merely
the cooling system functioning properly. The fan will
slow down when additional cooling is not required and
the clutch disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch disengages.
If a Tire Goes Flat
It's unusual for a tire to ªblow outº while you're driving,
especially if you maintain your tires properly. If air goes
out of a tire, it's much more likely to leak out slowly.
But if you should ever have a ªblowout,º here are a few
tips about what to expect and what to do:
If a front tire fails, the flat tire will create 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.
A rear blowout, particularly on a curve, acts much like a
skid and may require the same correction you'd use in a
skid. In any rear blowout, remove your foot from the
accelerator pedal. Get the vehicle under control by
steering the way you want the vehicle to go. It may be
very bumpy and noisy, but you can still steer. Gently
brake to a stop
-- well off the road if possible.
If a tire goes flat, avoid further tire and wheel damage
by driving slowly to a level place and turn on your
hazard warning flashers. The next part tells you what
to do.
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5-27
Changing a Flat Tire
Your truck, when new, did not include tire changing
equipment or a place to store a tire in the vehicle.
Few drivers of these vehicles have the necessary
equipment aboard to be able to change a flat tire safely.
For example, you would need a truck jack that can lift
several thousand pounds and a torque wrench that can
generate several hundred foot
-pounds (Newton-meters)
of twisting force.
CAUTION:
If you try to put air back into a tire that has run
flat, or even a tire that was quite low on air, the
tire can have a sudden air
-out. This could cause
you to lose control of the vehicle and have a
serious crash. Don't refill a flat or very low tire
with air without first having the tire taken off the
wheel and checked for damage.
So if you're stopped somewhere by a flat or damaged
tire or wheel, you should get expert help. See ªRoadside
Assistanceº in the Index.
CAUTION:
Your vehicle, when new, did not include tire
changing equipment or a place to store a tire in
the vehicle. Special tools and procedures are
required if a tire needs to be serviced. If these
tools and procedures aren't used, you or others
could be injured or killed while trying to change
or service a truck tire.
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6-58
Tires
Your new vehicle comes with high-quality tires made by
a leading tire manufacturer. If you ever have questions
about your tire warranty and where to obtain service, see
your General Motors Warranty booklet for details.
CAUTION:
Poorly maintained and improperly used tires are
dangerous.
Overloading your tires can cause
overheating as a result of too much friction.
You could have an air
-out and a serious
accident. See ªLoading Your Vehicleº in
the Index.
CAUTION: (Continued)
CAUTION: (Continued)
Underinflated tires pose the same danger as
overloaded tires. The resulting accident
could cause serious injury. Check all tires
frequently to maintain the recommended
pressure. Tire pressure should be checked
when your tires are cold.
Overinflated tires are more likely to be
cut, punctured or broken by a sudden
impact
-- such as when you hit a pothole.
Keep tires at the recommended pressure.
Worn, old tires can cause accidents. If your
tread is badly worn, or if your tires have
been damaged, replace them.
Page 313 of 386
6-59 Inflation -- Tire Pressure
The GVW Rating label, which is on the driver's door,
shows the correct inflation pressures for your tires
when they're cold. ªColdº means your vehicle has
been sitting for at least three hours or driven no more
than 1 mile (1.6 km).
NOTICE:
Don't let anyone tell you that underinflation or
overinflation is all right. It's not. If your tires
don't have enough air (underinflation), you can
get the following:
Too much flexing
Too much heat
Tire overloading
Bad wear
Bad handling
Bad fuel economy
NOTICE: (Continued)
NOTICE: (Continued)
If your tires have too much air (overinflation),
you can get the following:
Unusual wear
Bad handling
Rough ride
Needless damage from road hazards