Antilock Brake System (ABS)
Your vehicle has the Antilock Brake System (ABS), an
advanced electronic braking system that will help
prevent a braking skid.
When you start the engine and begin to drive away,
ABS will check itself. You might hear a momentary
motor or clicking noise while this test is going on. This
is normal.
If there is a problem with
ABS, this warning light will
stay on. SeeAnti-lock
Brake System (ABS)
Warning Light on
page 3-34.
Let us say the road is wet and you are driving safely.
Suddenly, an animal jumps out in front of you. You slam
on the brakes and continue braking. Here is what
happens with ABS:
A computer senses that wheels are slowing down. If
one of the wheels is about to stop rolling, the computer
will separately work the brakes at each wheel.ABS can change the brake pressure faster than any
driver could. The computer is programmed to make the
most of available tire and road conditions. This can
help you steer around the obstacle while braking hard.
As you brake, the computer keeps receiving updates
on wheel speed and controls braking pressure
accordingly.
Remember: ABS does not change the time you need
to get your foot up to the brake pedal or always
decrease stopping distance. If you get too close to
the vehicle in front of you, you will not have time to
apply the brakes if that vehicle suddenly slows or
stops. Always leave enough room up ahead to stop,
even though you have ABS.
Using ABS
Do not pump the brakes. Just hold the brake pedal
down firmly and let antilock work for you. You might feel
the brakes pulsate, or you might hear air exhausting
if your vehicle has air brakes, but this is normal.
Braking in Emergencies
With ABS, you can steer and brake at the same time.
In many emergencies, steering can help you more than
even the very best braking.
4-5
Highway Hypnosis
Always be alert and pay attention to your surroundings
while driving. If you become tired or sleepy, find a
safe place to park your vehicle and rest.
Other driving tips include:
•Keep the vehicle well ventilated.
•Keep interior temperature cool.
•Keep your eyes moving — scan the road ahead
and to the sides.
•Check the rearview mirror and vehicle instruments
often.
Hill and Mountain Roads
Driving on steep hills or through mountains is different
than driving on flat or rolling terrain. Tips for driving
in these conditions include:
•Keep your vehicle serviced and in good shape.
•Check all fluid levels and brakes, tires, cooling
system, and transmission.
•Going down steep or long hills, shift to a
lower gear.
{CAUTION:
If you do not shift down, the brakes could get
so hot that they would not work well. You
would then have poor braking or even none
going down a hill. You could crash. Shift down
to let the engine assist the brakes on a steep
downhill slope.
{CAUTION:
Coasting downhill in NEUTRAL (N) or with the
ignition off is dangerous. The brakes will have
to do all the work of slowing down and they
could get so hot that they would not work well.
You would then have poor braking or even
none going down a hill. You could crash.
Always have the engine running and your
vehicle in gear when you go downhill.
4-15
If You Are Caught in a Blizzard
If you are stopped by heavy snow, you could be in a
serious situation. You should probably stay with
your vehicle unless you know for sure that you are near
help and you can hike through the snow. Here are
some things to do to summon help and keep yourself
and your passengers safe:
•Turn on the hazard warning flashers.
•Tie a red cloth to your mirror arm to alert police that
you have been stopped by the snow.
•Put on extra clothing or wrap a blanket around you.
If you do not have blankets or extra clothing, make
body insulators from newspapers, burlap bags,
rags, floor mats — anything you can wrap around
yourself or tuck under your clothing to keep warm.
You can run the engine to keep warm, but be careful.
{CAUTION:
Snow can trap exhaust gases under your
vehicle. This can cause deadly CO (carbon
monoxide) gas to get inside. CO could
overcome you and kill you. You cannot see it
or smell it, so you might not know it is in your
vehicle. Clear away snow from around the
base of your vehicle if any is blocking your
exhaust pipe. And check around again from
time to time to be sure snow does not collect
there.
Open a window just a little on the side of the
vehicle that is away from the wind. This will
help keep CO out.
4-18
Service............................................................5-4
Accessories and Modifications..........................5-4
California Proposition 65 Warning.....................5-5
California Perchlorate Materials Requirements.....5-5
Doing Your Own Service Work.........................5-6
Engine Fan Breakage.....................................5-6
Fuel................................................................5-7
Gasoline Octane............................................5-7
Gasoline Specifications....................................5-7
Additives.......................................................5-8
Diesel Engine Fuel.........................................5-9
What Fuel to Use...........................................5-9
Very Cold Weather Operation.........................5-12
Water in Fuel...............................................5-12
Running Out of Fuel.....................................5-17
Fuel Filter Replacement.................................5-18
Fuels in Foreign Countries.............................5-19
Filling the Tank............................................5-20
Filling a Portable Fuel Container.....................5-21
Checking Things Under the Hood....................5-22
Hood Latches...............................................5-22
Engine Oil (Caterpillar
®Diesel Engine).............5-23
Engine Oil (Gasoline Engine)..........................5-24
Engine Oil (DURAMAX
®Diesel Engine)............5-28Engine Oil (Isuzu Diesel Engine).....................5-32
Engine Oil Life System (Gasoline Engine)........5-36
Engine Oil Life System (DURAMAX
®/Isuzu
Diesel Engines).........................................5-37
Engine Oil Life System (Caterpillar
®Diesel
Engine)....................................................5-39
Engine Air Cleaner/Filter................................5-39
Automatic Transmission Fluid.........................5-43
Manual Transmission Fluid.............................5-43
Engine Coolant (Caterpillar
®Diesel Engines).....5-44
Engine Coolant (Gas and DURAMAX®/
Isuzu 7.8L L6 Engines)..............................5-44
Coolant Surge Tank Pressure Cap..................5-47
Engine Overheating.......................................5-48
Cooling System............................................5-50
Engine Fan Noise.........................................5-54
Power Steering Fluid.....................................5-54
Windshield Washer Fluid................................5-55
Brakes........................................................5-57
Battery........................................................5-66
Jump Starting...............................................5-67
Rear Axle.......................................................5-72
Rear Axle Shift Motor....................................5-73
Section 5 Service and Appearance Care
5-1
6. Repeatedly push down
on the fuel filter primer
pump with the palm
of your hand. Let the
pump return upward
between pushes.
7. Operate the priming pump until a small amount of
fuel seeps from the vent valve. When you see the
fuel, the filter is now full of fuel and the system
should be primed.
8. Close the vent valve.
9. Clean any fuel which accumulated on the fuel filter.
10. Start the engine and let it idle for a few minutes.
11. Check the filter for leaks.Priming the 7.8L DURAMAX®Diesel
Engine
If your vehicle is equipped with the 7.8L DURAMAX®
diesel engine, use the following procedure to prime the
engine:
1. Make sure there is fuel in the fuel tank.
2. Make sure the specified fuel filter is properly
installed.
3. Make sure the fuel lines are securely connected.
4. Make sure the fuel filter is cool to the touch.
5-16
5. Use a clean cloth to remove dirt and oil from the
fuel filter head and breather valve.
6. Use the palm of your hand to repeatedly press and
release the plunger at the top of the fuel filter
priming pump. Continue until the plunger resistance
becomes firm. This may take from 20 to 100 times,
depending upon fuel tank location.
7. Turn the fuel filter breather valve screw
counterclockwise several turns to open the breather
valve.
8. Use the palm of your hand to repeatedly press and
release the plunger at the top of the fuel filter
priming pump until fuel begins to seep from the
breather valve.
9. Tighten the fuel filter breather screw to the specified
torque, 4.9Y(43 lbs in).
10. Use the palm of your hand to press and release the
plunger at the top of the fuel filter priming pump
about 20 more times. This sends fuel to the engine.
11. Use a clean cloth to remove any fuel from the fuel
filter and surrounding area.
12. Start the engine and allow it to idle for a
few minutes.
13. Check the fuel filter for leakage.Running Out of Fuel
If the diesel engine stalls and you think that you have
run out of fuel, do this to restart your engine:
{CAUTION:
Diesel fuel is ammable. It could start a re if
it gets on hot engine parts. You could be
burned. Do not let too much fuel ow from the
air bleed valve, and wipe up any spilled fuel
with a cloth.
1. If you are parked on a level surface, add at least
2 gallons (7.6 liters) of fuel. However, if you are
parked on a slope, you may need to add up to
5 gallons (18.9 liters) of fuel.
2. Follow the fuel priming procedure earlier in this
section to prime the fuel filter.
3. Close the air bleed valve.
5-17
5. Reinstall and tighten the filter container and
reconnect the water sensor wire to the filter.
6. Use the fuel filter priming procedure earlier in this
section to prime the fuel filter.
7. Tighten the air bleed valve by turning it clockwise
until hand-tight.
8. Start your engine and let it idle for five minutes.
Check your fuel filter and air bleed valve for
leaks.
How to Reset Fuel Filter Change
Light - DURAMAX®6.6L (LMM) Engine
The engine controller calculates when to change
the fuel filter based on vehicle and fuel use. Anytime
your fuel filter is changed, reset the fuel filter light so the
engine controller can calculate when the next fuel filter
change is required. If a situation occurs where you
change your fuel filter prior to a change fuel filter light
being turned on, reset the fuel filter change light.To reset the Fuel Filter Change light:
1. Turn the ignition key to RUN with the engine off
2. Fully press the accelerator and brake pedals at the
same time for 10 seconds. If the Fuel Filter Change
light flashes for 5 seconds, the system is resetting.
3. Turn the key to OFF
If the Fuel Filter Change light comes back on when you
start your vehicle, the light has not been reset. Repeat
the procedure. SeeChange Fuel Filter Warning Light on
page 3-44for more information.Fuels in Foreign Countries
If you plan on driving in another country outside the
United States or Canada, the proper fuel might be hard
to find. Never use leaded gasoline or any other fuel
not recommended in the previous text on fuel. Costly
repairs caused by use of improper fuel would not be
covered by your warranty.
To check the fuel availability, ask an auto club, or
contact a major oil company that does business in the
country where you will be driving.
5-19