Engine Starter Over-Crank
Protection
Your vehicle may have an engine starter over-crank
protection system. If the starter motor overheats and
shuts off due to over-cranking, the motor must cool down
before it will reset and allow starter operation. It can take
up to six minutes before the starter will work again.
Starting the Gasoline Engine
The 8th digit of your Vehicle Identification Number (VIN)
shows the code letter for your engine. Use this
number to verify the type of engine in your vehicle. See
Vehicle Identification Number (VIN) on page 5-101.
Follow the proper steps to start the engine.
To start a diesel engine, seeStarting the Diesel Engine
on page 2-14.
Automatic Transmission
Set the parking brake and move your shift lever to
NEUTRAL (N) or PARK (P), if so equipped. Your engine
will not start in any other position — that is a safety
feature.
Manual Transmission
Set the parking brake, shift to NEUTRAL (N) and
hold the clutch pedal to the floor while starting
the engine.
Starter Motor Operation
•The starter motor will disengage if you release the
key or the engine reaches a predetermined engine
speed.
•To prevent overheating, the starter motor will
disengage after continuously operating for
15 seconds. You must release the key from the
start position to re-engage the starter.
•The starter motor will not engage if the engine is
already running.
•The starter motor will disengage if, after
two seconds, the starter pinion gear does not
engage the flywheel or there is no engine rpm
signal from the engine speed sensor.
2-12
During this warm-up period, check your warning lights
and gages:
•If oil pressure does not begin to rise within
15 seconds of starting, stop the engine and find the
cause. SeeOil Pressure Gage on page 3-37for
more information.
•If the engine coolant temperature gage needle goes
into the hot area on the gage, stop the engine and
find the cause of the overheating. SeeEngine
Coolant Temperature Gage on page 3-35for more
information.
•If you have air brakes, the dual-needle air pressure
gage should read at least 115 psi (790 kPa) for both
service systems before you try to move the vehicle.
When air pressure is below 60 psi (420 kPa), the
LOW AIR light will come on and you will hear a tone
alarm. SeeBrake System Warning Light on
page 3-32for more information. If the pressure does
not build up or drops during warm-up, stop the
engine and find the cause before you try to move the
vehicle. Recommended air pressure before driving is
120 psi (830 kPa). SeeAir Pressure Gage on
page 3-46for more information.
•The charging system light should come on when the
ignition key is turned to ON/RUN or START and
should go out when the engine is running above idle.
If the light does not go out or comes back on during
normal engine operation, have the charging system
checked right away. (This light tells you if the
generator is not charging; it does not reflect the
condition of the battery.) SeeCharging System Light
on page 3-30for more information.
•The voltmeter charge indicator gage tells you the
condition of your battery’s charge. The gage should
be in the center area during engine operation. The
red area on the left indicates an undercharge
condition; the red area on the right indicates an
overcharge. If the gage is in either red area, have the
battery and charging system checked right away.
SeeVoltmeter Gage on page 3-31for more
information.
Notice:Do not allow the engine to operate at low
idle for more than ve minutes. This can cause
low engine operating temperatures which can affect
engine operation and reduce engine life. Engine
idle speed should be increased to 1200 rpm
whenever extended idle is required. Once started,
the engine should be placed under load to allow the
engine coolant temperature to reach 150°F (66°C)
before shutting off the engine.
2-24
Ashtray(s) and Cigarette Lighter
Your vehicle may have an ashtray and a cigarette lighter
located in the center floor console. To open the
removable ashtray, flip open the top.
Notice:If you put papers, pins, or other ammable
items in the ashtray, hot cigarettes or other
smoking materials could ignite them and possibly
damage your vehicle. Never put ammable items in
the ashtray.
To use the cigarette lighter, push it in all the way and
let it go. When it’s ready, it will pop back out by itself.
Notice:Holding a cigarette lighter in while it is
heating does not let the lighter back away from the
heating element when it is hot. Damage from
overheating can occur to the lighter or heating
element, or a fuse could be blown. Do not hold a
cigarette lighter in while it is heating.
Climate Controls
Climate Control System
With these systems, you can control the heating,
cooling, and ventilation for your vehicle.
If your vehicle does not have air conditioning,
the controls will look like this:
9(Fan):Turn the left knob clockwise or
counterclockwise to increase or decrease the fan
speed. To increase airflow, turn the knob clockwise.
To decrease airflow, turn it counterclockwise. To turn
the fan off, turn the mode knob on the far right
counterclockwise to the off position.Vehicles Without Air Conditioning
3-20
Engine Coolant Temperature Gage
This gage shows the
engine coolant
temperature. If the gage
pointer moves into the
red area, your engine
coolant might have
overheated and your
engine may be too hot.
You should pull off the road, stop your vehicle and turn
off the engine as soon as possible.
SeeEngine Overheating on page 5-48. If you have a
Caterpillar
®diesel engine, also see your Caterpillar®
Operation & Maintenance Manual.
Low Coolant Warning Light
Your vehicle has a low
coolant warning light.
If this light comes on, the
system is low on coolant
and the engine may
overheat.
The warning light should come on briefly, as a check,
when you turn on the ignition.
When it comes on, you will also hear a warning tone for
10 seconds. SeeEngine Coolant (Caterpillar
®Diesel
Engines) on page 5-44orEngine Coolant (Gas and
DURAMAX
®/Isuzu 7.8L L6 Engines) on page 5-44
Engine Coolant and have your vehicle serviced as
soon as you can.
This light may also come on if your vehicle has the
automatic engine shutdown system and engine
shutdown has begun. SeeEngine Alarm and Automatic
Shutdown on page 2-18for more information.
3-35
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
How to Add Fluid
To add transmission fluid, do the following:
1. Remove the filler plug.
2. Add fluid at the filler plug hole. Add only enough
fluid to bring the fluid level up to the bottom of
the fill opening. Refer to the Maintenance
Schedule to determine the proper fluid to use.
SeePart C: Recommended Fluids and Lubricants
on page 6-31.
3. Reinstall the filler plug. Be sure the plug is fully
seated.
Engine Coolant (Caterpillar®Diesel
Engines)
If your vehicle has a Caterpillar®diesel engine, see the
Caterpillar®Diesel Engine Operation & Maintenance
Manual provided with your vehicle to find out what to
add, as well as when and how to service your cooling
system.
Engine Coolant (Gas and
DURAMAX
®/Isuzu 7.8L L6 Engines)
The cooling system in your vehicle is filled with
DEX-COOL®engine coolant. This coolant is designed
to remain in your vehicle for five years or 150,000 miles
(240 000 km), whichever occurs first, if you add only
DEX-COOL
®extended life coolant.
The following explains your cooling system and how to
add coolant when it is low. If you have a problem with
engine overheating, seeEngine Overheating on
page 5-48.
A 50/50 mixture of clean, drinkable water and
DEX-COOL
®coolant will:
•Give freezing protection down to−34°F (−37°C).
•Give boiling protection up to 265°F (129°C).
•Protect against rust and corrosion.
•Help keep the proper engine temperature.
•Let the warning lights and gages work as they
should.
Notice:Using coolant other than DEX-COOL
®may
cause premature engine, heater core or radiator
corrosion. In addition, the engine coolant may
require changing sooner, at 30,000 miles (50 000 km)
or 24 months, whichever occurs rst. Any repairs
would not be covered by your warranty. Always use
DEX-COOL
®(silicate-free) coolant in your vehicle.
5-44
Engine Overheating
You will find an engine coolant temperature gage, as
well as a low coolant warning light, on your vehicle’s
instrument panel. SeeEngine Coolant Temperature
Gage on page 3-35andLow Coolant Warning Light on
page 3-35for more information.
Your vehicle also has a check gages warning light on
the instrument panel. SeeCheck Gages Warning
Light on page 3-42for more information.
If Steam Is Coming From Your Engine
{CAUTION:
Steam from an overheated engine can burn
you badly, even if you just open the hood. Stay
away from the engine if you see or hear steam
coming from it. Just turn it off and get
everyone away from the vehicle until it cools
down. Wait until there is no sign of steam or
coolant before you open the hood.
If you keep driving when your engine is
overheated, the liquids in it can catch re. You
or others could be badly burned. Stop your
engine if it overheats, and get out of the
vehicle until the engine is cool.
Notice:If your engine catches re because you
keep driving with no coolant, your vehicle can
be badly damaged. The costly repairs would not be
covered by your warranty.
5-48
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 vehicle Warranty
booklet for details.
{CAUTION:
Poorly maintained and improperly used
tires are dangerous.
Overloading your vehicle’s tires can
cause overheating as a result of too
much exing. You could have an
air-out and a serious accident. See
Loading Your Vehicle on page 4-21.
Underin ated 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 vehicle’s tires are cold. See
Inflation - Tire Pressure on page 5-82.
CAUTION: (Continued)
CAUTION: (Continued)
Overin ated 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
the tire’s tread is badly worn, or if
your vehicle’s tires have been
damaged, replace them.
In ation - Tire Pressure
Tires need the correct amount of air pressure to operate
effectively. The Certification or Tire Information label
shows the correct inflation pressures for your tires when
they are cold. Cold means your vehicle has been
sitting for at least three hours or driven no more than
1 mile (1.6 km).
5-82