Gasoline Engine Warm-Up
When you’ve started your engine, let it run for
20 or 30 seconds to warm up before you put a load on
the engine.
Drive at moderate speeds for the first few miles,
especially in cold weather. Running a cold engine at
high speed can damage it. SeeHigh Idle Systemunder
Starting Your Diesel Engine on page 2-14
Restarting the Gasoline Engine While
Moving (Automatic Transmission)
If you have to restart the engine while the vehicle is
moving, you’ll first have to shift the automatic
transmission to NEUTRAL (N). This safety feature
prevents starting the engine when the transmission is in
a drive gear.
Stopping the Gasoline Engine
Let your engine idle for a few seconds before turning it
off after you have finished driving your vehicle.
If you shift to NEUTRAL (N) or PARK (P), set the
parking brake.
If your vehicle has a two-speed axle, put the range
selector in LOW. To be sure the axle has shifted into
LOW, engage the clutch and transmission; the vehicle
may move slightly when you do this.While your engine is idling before you turn it off, you
can make a list of any operational or handling concerns
to give to responsible maintenance personnel so
they can handle them right away.
Moisture will condense in a fuel tank that is almost
empty if the engine has not run for a while, even just
overnight under some conditions. So, it’s always best to
refuel your vehicle at the end of each run.
Starting Your Diesel Engine
If you have a Caterpillar®diesel engine, also refer to
your Caterpillar®Diesel Engine Operation &
Maintenance Manual for starting procedure.
For vehicles with the DURAMAX™ diesel engine, also
seeStarting Your DURAMAX™ Diesel Engine on
page 2-19.
To make starting easier in cold weather (below 32°F or
0°C), the proper viscosity engine oil should be used.
SeeEngine Oil (Caterpillar
®Diesel Engine) on
page 5-20orEngine Oil (Gasoline Engine) on page 5-20
orEngine Oil (DURAMAX™ Diesel) on page 5-25. It’s
also best to heat the engine oil first. You can do this by
using an engine coolant heater.
If you ever need to have your vehicle towed, see
Towing Your Vehicle on page 4-31.
2-14
The manual high idle feature is activated by pressing
the switch on the instrument panel. When the switch is
pressed again, or any of the previous conditions are
not met, manual high idle will be deactivated.
The manual high idle has been preset at the factory.
Your dealer may change the setting to fit your needs.
For vehicles with Caterpillar
®diesel engines, manual
high idle can be used to set any desired high idle speed.
To set a new temporary engine idle speed:
1. Make sure all of the previously described conditions
are met.
2. Press the accelerator pedal to the desired engine
speed.
3. Momentarily press the manual high idle switch.
The temporary high idle speed will be set. This new high
idle rpm level will be remembered by the system until
either the ignition is turned to OFF or a new high
idle speed is set.
Exhaust Restrictor (Diesel Engines)
If your vehicle is equipped with this feature, there is an
exhaust restrictor valve located in the exhaust stream.
The valve closes to provide back pressure to the engine
for the purpose of warming the engine quickly.The exhaust restrictor operates:
•while the engine is running.
•while the vehicle is not moving.
•while the accelerator, brake and clutch pedals are
not pressed.
•while idling or driving in cold temperatures.
•when the shift lever is in NEUTRAL (N) or
PARK (P).
On vehicles equipped with a diesel engine exhaust
brake, the exhaust brake switch must be on. The
indicator in the exhaust brake switch will be lit when the
exhaust restrictor is active. The exhaust brake
indicator light in the center of the instrument panel will
also be lit whenever the exhaust restrictor is active.
When the engine coolant temperature is below 149°F
(65°C) and the outside temperature is below 50°F
(10°C), the exhaust restrictor will come on within
45 seconds of starting the engine. After running the
engine for an additional 45 seconds, the engine idle will
increase.
The exhaust restrictor will shut off and engine idle will
return to normal once the engine is warmed up, or
the transmission is shifted into range.
2-18
When the engine is started, it will slowly ramp up to the
high idle speed after a delay of a few seconds up to
about two minutes. For this method to work properly
there must be no throttle or brake pedal faults, and the
throttle pedal must not fall below 75 percent of wide
open throttle while pressing the brake pedal.
The engine idle speed will return to normal once the
following conditions are met:
•Once engine coolant temperature reaches
150°F (65°C).
•Air intake temperature reaches 41°F (5°C).
The high idle speed will be temporarily interrupted and
the engine speed will return to normal if any of the
following conditions occur:
•The brake pedal is applied.
•The accelerator pedal is pressed.
•The automatic transmission is shifted out of
PARK (P) or NEUTRAL (N).
•The clutch pedal on the manual transmission is
pressed.
•Vehicle speed is detected.
Once these inputs are removed, the engine idle speed
will slowly ramp back up to high idle after the normal
delay, if the conditions for engine coolant temperature
and air intake temperature are still met.
Engine Checks Before Operating
When you’ve started your engine, let it run for
20 to 30 seconds before you put a load on the engine.
Butdon’tleave the vehicle while the engine is running.
Avoid unnecessary idling of diesel engine equipped
vehicles.
If the engine idles too long, the temperature of the
engine coolant will fall below the normal operating
range. Low engine operating temperature causes
several conditions which affect engine operation and
reduce engine life.
The engine should be permitted to go through a
warm-up period. Operate the vehicle at a minimum of
600 rpm during the warm-up period. During this
period and during operation, the following observations
should be made.
During this warm-up period, check your warning lights
and gages:
•If oil pressure doesn’t begin to rise within
15 seconds of starting, stop the engine and find the
cause.
•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.
2-22
•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. If the pressure doesn’t
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 actually
driving away is 120 psi (830 kPa).
•The charging system light should come on when
the ignition key is turned to RUN or START and
should go out when the engine is running above
idle. If the light doesn’t 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 doesn’t
reflect the condition of the battery.)
•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.Notice:For diesel engines, don’t 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.
Engine Coolant Heater
If your vehicle has this
feature, the plug-in
receptacle is located under
the driver’s door.
In very cold weather, 0°F (−18°C) or colder, the engine
coolant heater can help. You’ll get easier starting
and better fuel economy during engine warm-up.
2-23
Diesel Engine Exhaust Brake
The exhaust brake is available on vehicles equipped
with a diesel engine. It is located in the exhaust system.
The exhaust brake is used to help slow the vehicle
and may assist the vehicle’s foundation brakes. The use
of the exhaust brake will assist the braking of the
vehicle and prolong the life of the foundation brake
lining material.
The exhaust brake switch
is located in the instrument
panel switchbank.
Push the bottom of the switch to turn the exhaust brake
on. When you push the top of the switch, the exhaust
brake will turn off.There is an indicator light on the instrument panel
similar to the symbol on the switch, that will come on
when the exhaust brake is active. SeeExhaust
Brake Indicator Light on page 3-40for more information.
When using the exhaust brake, the proper gear range
selection is important. The exhaust brake will be
most effective if the gear range selected is the lowest
possible range that does not allow the engine rpm to go
more than 200 rpm above rated (full load) rpm. If you
have a Caterpillar
®diesel engine, do not exceed
2900 rpm. If you have a DURAMAX™ (LG4) diesel
engine, do not exceed 2400 rpm. If you have a
DURAMAX™ (LB7) diesel engine, do not exceed
3600 rpm.
If you have an automatic transmission and press this
button, the transmission will downshift to a factory
default setting of fourth gear. To change the default
setting, or for more information on factory default
settings, contact your dealer for assistance.
The accelerator and clutch pedals must be released in
order for the exhaust brake to engage. The exhaust
brake will not function when the cruise control feature is
active, and will automatically shut off when the
anti-lock brake system is active.
2-25
Air Shift Control (Automatic
Transmission)
The rear axle shift control
switch for an automatic
transmission is located in
the instrument panel
switchbank.
Press the bottom of the switch to get to the low range.
The switch indicator light will come on when the
vehicle is in low range. Press the top of the switch to
return to the high range.
The two-speed axle should be in low range when you
park the vehicle. You’ll need to engage the transmission,
even moving the vehicle a little, to be sure the axle is
in low range. Then shift into PARK (P), apply the parking
brake and shut off the engine.To shift up from low to high, press the top of the rear
axle shift control switch and press down on the
accelerator. When you shift the axle from high to low,
press the bottom of the switch, release the accelerator
and then quickly press it down again.
To operate off-road or under a heavy load, shift into low
range when the vehicle is standing still and then
operate the transmission normally.
On the highway, with the axle in low range and the
transmission in top gear, you may shift the axle to high
range by raising the switch and releasing the
accelerator momentarily. Reapply the accelerator after
you shift.
Under light load conditions, first shift the axle into the
high range with the vehicle at a standstill and then
operate the transmission normally.
Air Suspension
Your vehicle may be equipped with the Hendrickson
HAS Series single-axle air suspension which is designed
for single-axle on-highway use. The feature is available
in 19,000 lb. (8 618.3 kg), 21,000 lb. (9 525.4 kg)
and 23,000 lb. (10 432.6 kg) capacities for operations
which require extra cubic capacity and a reduced
deck height.
2-27
Rear Air Suspension Dump Control
If your vehicle is equipped with the Hendrickson HAS
Series single-axle air suspension, you have this control.
The air suspension dump control allows the operator
to lower the deck height approximately 4.5 inches
(11.5 cm) from the normal frame height.
The switch to deflate and
inflate the air suspension
is located in the instrument
panel switchbank.
Press the bottom of the switch to deflate the air
suspension and lower the deck height. Press the top of
the switch to return the suspension to normal deck
height.
An indicator light will come on and stay on whenever
the switch is in the dumped position.
Automatic Transmission Operation
We build vehicles with five and six-speed automatic
transmissions. This part of the manual covers the basics
of these. With some of the transmissions, you will find
another manual in your vehicle that goes into more
detail. On the headliner, in front of and above the driver,
or in some other place near the driver, you will see a
label that describes important operating facts about the
automatic transmission in your vehicle. Make sure
you follow the instructions on this label.
Be sure to keep your parking brake set until you are
ready to shift into DRIVE (D), and press the brake pedal
while shifting from NEUTRAL (N) or PARK (P) to a
drive gear.
All vehicles equipped with automatic transmissions can
be started in PARK (P), if equipped, or in NEUTRAL (N).
See the Allison
®Transmission Operator’s Manual in
your vehicle for more information about this.
2-28