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
Starting Your Engine
1. Turn your ignition key to RUN.
Observe the wait to start light. SeeWait to Start
Indicator on page 3-36. This light may not come on
if the engine is hot.
If you have a Caterpillar
®diesel engine, see your
Caterpillar®Diesel Engine Operation & Maintenance
Manual for proper wait to start light operation.
2. As soon as the wait to start light goes off,
immediately turn the ignition key to START. When
the engine starts, let go of the key.
If your vehicle is equipped with a DURAMAX
®6600
Diesel Engine, it has a fast warm-up glow plug
system. The wait to start light will illuminate for a
much shorter time than most diesel engines, due to
the rapid heating of the glow plug system.
Notice:Holding your key in START for longer than
15 seconds at a time will cause your battery to
be drained much sooner. And the excessive heat
can damage your starter motor.Notice:If the wait to start light stays on after
starting your vehicle, your vehicle may not run
properly. Have your vehicle serviced right away.
3. If the engine does not start after 15 seconds
of cranking, turn the ignition key to OFF. Wait
one minute for the starter to cool, then try the same
steps again.
If you are trying to start your engine after you have run
out of fuel, seeRunning Out of Fuel on page 5-17.
When your engine is cold, let it run for a few minutes
before you move your vehicle. This lets oil pressure
build up. Your engine will sound louder when it is cold.
Notice:If you are not in an idling vehicle and
the engine overheats, you would not be there to see
the overheated engine indication. This could
damage your vehicle. Do not let your engine run
when you are not in your vehicle.
2-15
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
Engine Coolant Heater
The engine coolant heater, if available, can help in cold
weather conditions at or below 0°F (−18°C) for easier
starting and better fuel economy during engine warm-up.
Plug in the coolant heater at least four hours before
starting your vehicle.
To Use the Engine Coolant Heater
1. Turn off the engine.
2. Find the plug-in outlet located under the
driver’s door.
3. Plug it into a normal, grounded 110-volt AC outlet.
{CAUTION:
Plugging the cord into an ungrounded outlet
could cause an electrical shock. Also, the
wrong kind of extension cord could overheat
and cause a re. You could be seriously
injured. Plug the cord into a properly grounded
three-prong 110-volt AC outlet. If the cord will
not reach, use a heavy-duty three-prong
extension cord rated for at least 15 amps.
4. Before starting the engine, be sure to unplug and
store the cord as it was before to keep it away
from moving engine parts. If you do not, it could be
damaged.
How long should you keep the coolant heater plugged
in? The answer depends on the outside temperature, the
kind of oil you have, and some other things. Instead
of trying to list everything here, we ask that you contact
your dealer/retailer in the area where you will be
parking your vehicle. The dealer/retailer can give you
the best advice for that particular area.
2-25
Shifting Out of NEUTRAL
To shift the transfer case out of NEUTRAL, do the
following:
1. Set the parking brake. SeeParking Brake (With
Hydraulic Brakes) on page 2-38orParking Brake
(With Air Brakes) on page 2-41for parking
brake apply procedure.
2. Apply the regular brake pedal.
3. Turn the ignition to ON/RUN with the engine off.
4. Put the transmission in NEUTRAL (N).
5. Turn the transfer case knob to the desired shift
position (Two-Wheel High, Four-Wheel High,
Four-Wheel Low).
6. After the transfer case has shifted out of NEUTRAL,
the indicator light goes out.
Notice:Driving with the parking brake on can
overheat the brake system and cause premature
wear or damage to brake system parts. Verify that
the parking brake is fully released and the brake
warning light is off before driving.7. Release the parking brake.
8. Start the engine and shift the transmission lever to
the desired position.
Excessively shifting the transfer case into or out of the
different modes can cause the transfer case to enter the
shift protection mode. This protects the transfer case from
possible damage and only allows the transfer case to
respond to one shift per 10 seconds. The transfer case
can stay in this mode for up to three minutes.
Parking
{CAUTION:
If you do not park your vehicle properly, it can
roll. If you have left the engine running, it can
move very quickly. You or others could be
injured. To be sure your vehicle will not move,
even when you are on level ground, follow the
steps below.
2-37
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
Run your engine only as long as you must. This saves
fuel. When you run the engine, make it go a little
faster than just idle. That is, push the accelerator
slightly. This uses less fuel for the heat that you get and
it keeps the battery (or batteries) charged. You will
need a well-charged battery (or batteries) to restart the
vehicle, and possibly for signaling later on with the
headlamps. Let the heater run for a while.
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.If Your Vehicle is Stuck in Sand,
Mud, Ice, or Snow
Slowly and cautiously spin the wheels to free your
vehicle when stuck in sand, mud, ice, or snow. See
Rocking Your Vehicle to Get It Out on page 4-20.
If your vehicle has a traction system, it can often help to
free a stuck vehicle. Refer to your vehicle’s traction
system in the Index. If the stuck condition is too severe
for the traction system to free the vehicle, turn the
traction system off and use the rocking method.
{CAUTION:
If you let your vehicle’s tires spin at high
speed, they can explode, and you or others
could be injured. The vehicle can overheat,
causing an engine compartment re or other
damage. Spin the wheels as little as possible
and avoid going above 35 mph (55 km/h) as
shown on the speedometer.
4-19
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