light CHEVROLET LOW CAB FORWARD 2020 Workshop Manual

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
122 Climate Controls
O:Use this position to prevent
dusty or otherwise contaminated
outside air from entering the cab,
such as in a tunnel or in congested
traffic.
Extended use of the inside air
recirculation position causes the
windshield and windows to fog up
easily, making visibility poor. For
good ventilation, switch to outside
air as soon as possible.
Temperature Control Knob : Use
this knob to select the preferred cab
interior temperature. Turn the knob
counterclockwise to lower the outlet
air temperature and clockwise to
raise it.
Fan Speed Control Knob : The fan
speed can be adjusted to any of the
four speeds available.
Air Conditioning (A/C) Switch :
Press this switch to use the air
conditioning system. The indicator
light inside the switch will come on
to show that the air conditioning
system is in operation. The air
conditioning system can also be
used for dehumidifying while the heater is being used. To turn off the
air conditioning, push this switch in
again.
When the defrost mode is selected,
the air conditioner compressor will
be on.
Even if the A/C switch is turned on,
the air conditioning system will not
operate when the fan speed control
knob is placed in the stop position.
Make sure that the fan speed
control knob is in a position other
than the stop position.
Even in seasons when the air
conditioning system is not used,
occasionally operate the system for
a few minutes with the engine
running at a low speed in order to
keep the system's components
lubricated.
Ventilation
Outside Air Ventilation :
Press the
A/C switch to the off position. Turn
the outlet selector knob to the
preferred position. Move the air
selector lever to the
Pposition. Set the temperature control knob to
the desired position. Adjust the fan
speed control knob to the preferred
speed.
How to Use the Heater
Normal Heating :
Set the outlet
selector knob to the
6or-
position. Use the-position for
warming your feet while defogging
the windshield.
Set the air selector lever to the
P
position. Adjust the temperature
control knob and the fan speed
control knob to the desired
positions.
To dehumidify the cab interior while
heating, press the A/C switch to the
on position.
As the heater uses the heat from
the engine coolant, its heating effect
is weak when the engine coolant
temperature is low.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
Climate Controls 123
Maximum Heating :Turn the outlet
selector knob to the
6position, set
the air selector lever to the
O
position, and turn the temperature
control knob fully towards the high
temperature direction.
Set the fan speed control knob to
the maximum speed position.
Bi-Level Heating : Set the outlet
selector knob to the
)position. Set
the air selector lever to the
P
position. Set the temperature control
knob to the middle position.
Adjust the fan speed control knob
as desired. The air from the floor
outlets is warmer than the air from
the upper outlets in this position.
However, when the temperature
control knob is moved to either the
full hot or the full cold position, the
air from the floor outlets and the air
from the upper outlets will be the
same temperature. This position can
give cool upper level air and warm
floor level air when the temperature
control is adjusted in between cold and hot. This is useful in cool
weather with bright sunlight
conditions.
Defogging and Defrosting the
Windshield
Defogging :
Set the outlet selector
knob to the
1position. Set the air
selector lever to the
Pposition.
Turn the temperature control knob
to a high-temperature position
according to your preference. For
defogging in the summer months,
set the temperature control knob to
any desired position.
Set the fan speed control knob to
any speed position, except the off
position. The A/C compressor
automatically operates when the
1
position is selected. Defogging is
performed very effectively with the
dehumidifying effect.
Defrosting : Set the outlet selector
knob to the
1position. Set the air
selector lever to the
Oposition. Turn the temperature control knob
fully towards the high-temperature
direction. Set the fan speed control
knob to the maximum speed
position.
After defrosting, be certain to return
the air selector lever to the
P
position. Failure to do so will cause
the windshield to fog up, impeding
forward visibility.
Cooling
Normal/Moderate Cooling :
This
setting is suitable for extended
periods of cooling or moderate
cooling. Press the A/C switch to the
on position.
Set the outlet selector knob to the
Hposition for normal cooling or set
it to the
)position for moderate
cooling. Adjust the temperature
control knob to the desired position.
Adjust the fan speed control knob
as desired

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
124 Climate Controls
Maximum Cooling :Set the outlet
selector knob to the
Hposition.
Press the A/C switch to the on
position. Move the air selector lever
to the
Oposition
Turn the temperature control knob
fully towards the low-temperature
direction. Set the fan speed control
knob to the maximum speed
position.
After prolonged parking in direct
sunlight, open the windows or doors
to ventilate the interior of the cab
and release the heat.
During cooling operation, mist may
come out of the air outlets. This
results from quick cooling of humid
air, and does not indicate any
problem.
After maximum cooling, be certain
to return the air selector lever to
the
Pposition. Failure to do so will
cause the windshield to fog up,
impeding forward visibility.
Air Vents
1. Driver Side Outlets. Airflow direction is adjustable.
2. Windshield Outlets. Air is delivered towards the
windshield.
3. Passenger Side Outlets. Airflow direction is
adjustable. 4. Door Windows Outlet. Air is
delivered towards the door
windows
5. Foot Outlets. Air is delivered towards the feet.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
130 Driving and Operating
The careful attention you give your
vehicle, as far as maintenance is
concerned, will also help fuel
economy.
Protection of Engine against
Overcooling
Overcooling of the engine not only
accelerates wear of the vital engine
parts but also hurts fuel economy.
Distracted Driving
Do Not Use a Mobile Phone
While Driving
{Warning
Drivers should never use mobile
telephones or car phones in any
mode other than Hands Free
while driving. Doing so is
dangerous. Using a mobile
telephone while driving could
result in a crash because you
would not be paying full attention
to your surroundings. If you are(Continued)
Warning (Continued)
driving and you wish to use a
mobile telephone, first stop the
vehicle in a safe place.
You and others could be seriously
injured.
Control of a Vehicle
Warnings for Driving
{Warning
Concentrate on driving safely,
obeying all legally designated
speed limits, road signs and
traffic signals.
If you notice any abnormal noise,
abnormal smell or abnormal
vibration from any part of the
vehicle, immediately stop the
vehicle in a safe place and
perform checks.
(Continued)
Warning (Continued)
If a warning light comes on or a
buzzer sounds while you are
driving, immediately stop the
vehicle in a safe place and
perform checks.
Slow down sufficiently when
approaching a curve. Applying the
brakes or sharply turning the
steering wheel while turning the
curve could cause the cargo to
shift, the tires to slip and the
vehicle to tip onto its side.
Avoid scraping the tire sidewalls
against curbstones or driving over
dips and protrusions in the road
surface. You could damage the
tires, resulting in a blowout or
flat tire.
You and others could be seriously
injured.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
Driving and Operating 131
Pulling Away After Stopping
and Parking
Before pulling away, check that
there are no children or obstructions
around the vehicle and confirm that
it is safe to pull away.
If you cannot see the area behind
your vehicle well enough to confirm
it is safe to back up, get out of the
vehicle and check behind it.
Make it a habit to look around and
confirm that it is safe to pull away
after a temporary stop (at traffic
lights, for example).
If the Windshield Fogs Up
Use the heater to blow hot air on the
windshield or dehumidify the cabin
using the air conditioner and place
the outlet selector knob in the
5or
4position.
Place the air selector lever in the
outside air position.
Nighttime Visibility
If there is an old film on the
windshield, the lights of oncoming
traffic will be reflected in many directions, making it hard for you to
see ahead. Use glass cleaner to
clean the glass and the wiper
blades.
Worn wiper blades cannot wipe the
windshield clean and thus cannot
maintain visibility. When the wiper
blades become worn, replace them
with new ones.
Do Not Attach Accessories to
the Windshield or Windows
{Warning
Do not attach ornaments, films or
other accessories to the
windshield or windows. They
would impair visibility. Also, any
plastic suction cups used to
attach accessories could cause a
fire or a crash by acting as
lenses.
You and others could be seriously
injured.
Never Stop the Engine While
Driving
{Warning
Do not move the engine control
switch away from the "ON"
position while the vehicle is being
driven.
If the engine stops while the
vehicle is moving, the brake
booster does not work, and the
brakes would not work properly.
The engine could also be
damaged.
Stopping the engine while driving
would be extremely dangerous
because the power steering
would stop working, making the
steering wheel extremely hard
to turn.
Stopping the engine while driving
would be extremely dangerous
because the warning lights,
(Continued)

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
132 Driving and Operating
Warning (Continued)
indicator lights and other
electrical circuitry would
completely stop working.
Placing the engine control switch
in the "LOCK" position while
driving would be extremely
dangerous because the key could
come out, causing the steering
wheel to lock so that you could
not turn it.
You and others could be seriously
injured.
Avoid Unnecessary Idling of
the Engine
If the engine idles too long, the
engine coolant temperature will fall
below the operating range. Low
engine operating temperature
causes several conditions that are
harmful to engine operation and life.
Incomplete combustion of fuel in an
engine that is not fully warmed-up
causes crankcase dilution and
forms lacquer and gummy depositson valves, pistons, and rings. It also
causes rapid accumulation of
sludge within the engine.
Driving at Night
Nighttime driving is more dangerous
than daytime driving because the
field of view is narrower. Keep your
speed down, and maintain an ample
headway distance.
Metallic Plinking Sound from
the Muffler
Immediately after stopping the
engine, you may hear a metallic
plinking sound from the muffler. This
sound occurs as the muffler cools
down and contracts. It does not
indicate an abnormality or
breakdown.
When the Silencer and
Exhaust Pipe are Hot
{Warning
When the engine is running and
immediately after vehicle
operation, the DPF, silencer, and
exhaust pipe are extremely hot.
Be careful not to inadvertently
touch them when working near
them (for example, tilting the cab
or operating an attachment). You
and others could be seriously
injured.
Recommendations for Driving
in Hot Regions
The engine is more likely to
overheat in an environment where
the ambient temperature is high. To
prevent the engine from
overheating, pay attention to the
following points:
.
If the engine does not contain
the appropriate concentration of
engine coolant, overheating is
likely to occur.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
Driving and Operating 133
Refer toEngine Coolant 0243.
. Do not put well water, river water
or other hard water in the engine
cooling system. It would hasten
the formation of rust and scale.
. If foreign matter (insects, mud,
etc.) gets stuck in the radiator's
air passages, the cooling
system's performance will
deteriorate. Check the air
passages for clogging, and
remove any foreign matter using
water under low pressure.
Refer to Exterior Care 0307.
When Turning, the Rear
Wheels will Follow Tighter
Curves than the Front Wheels
Use the mirrors to confirm safety.
Sidewinds
If the vehicle catches a sidewind
and drifts sideways, firmly grip the
steering wheel, decelerate to a
speed that allows you to stay
completely in control, and make a directional correction. The vehicle
may catch strong sidewinds in the
following situations:
.
Emerging from a tunnel
. Driving over a bridge
. Driving on an embankment
. Driving through a cutting
. Being overtaken by a large truck
or bus
. Overtaking a large truck or bus
Flat Tire
If a blowout or flat tire occurs while
you are driving, calmly grip the
steering wheel and gradually apply
the brakes to decelerate. (Hard
braking would be dangerous
because it could cause the steering
wheel to be pulled to one side.)
Stop the vehicle in a safe place, and
change the tire.
Hard Bump Under Vehicle
If the underside of the vehicle
receives a hard bump, stop in a safe
place where the vehicle will not
obstruct traffic and check for brake fluid leakage, fuel leakage and
component damage. If any part of
the vehicle is damaged or broken,
promptly have the vehicle inspected
and repaired.
Highways
.
Speeds on highways are higher
than those on regular roads, so
there is more danger. Also, a
breakdown on a highway
represents a hazard to other
vehicles and can cause a crash.
Concentrate on safe driving.
Remember to perform daily
pre-operation inspections and
use highway driving techniques.
When performing daily
pre-operation inspections,
perform the checks shown in the
table on the left with particularly
great care.
Refer to Owner Checks and
Services 0330.
. When merging with traffic on a
highway, use the turn signal
lights to indicate your intentions
ahead of time. Speed up
sufficiently when you are in the

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
134 Driving and Operating
acceleration lane. Pay attention
to vehicles behind you and to
conditions in the lane you are
joining. Merge in such a way that
you do not obstruct vehicles in
the lane.
. Your sense of how fast you are
traveling becomes distorted on
long highway drives. Constantly
keep an eye on the
speedometer, and maintain a
suitable headway distance.
. During high-speed driving, even
a little turn of the steering wheel
causes a big movement of the
vehicle. Turn the steering wheel
slowly.
. Excessive use of the brake
pedal is extremely dangerous
because it rapidly wears the
brake linings and causes brake
fade. Make effective use of the
engine brake and the exhaust
brake when you want to
decelerate.
. When you want to turn off a
highway, use the turn signal
lights to indicate your intentions ahead of time. Paying attention
to vehicles behind you, turn off
the highway smoothly so as not
to obstruct other vehicles.
Brake Fade : Frequent use of the
brakes can cause the brakes to
overheat so that the frictional force
of the brake linings decreases and
the brakes become less effective
than normal. This phenomenon is
called brake fade.
Braking
Brake Operation
The brakes give strong braking
force with only light pressure on the
pedal. Do not press the brake pedal
hard except in the event of an
emergency.
Actual stopping distances vary
greatly. Your ability to stop safely
will be greatly affected by the
surface of the road, whether it is
pavement or gravel; the condition of
the road, whether it is wet, dry or
icy; tire tread; the condition of the
brakes; the weight of the vehicle;
the weight of the load; and the amount of brake force applied.
Please allow for realistic stopping
distances to avoid unnecessary
heavy braking. That means better
braking, longer brake life and safer
driving.
Stopping DistanceThe stopping distance of a vehicle
involves reaction time and braking
distance. Deciding to push the
brake pedal is reaction time.
Applying the brake pedal until the
vehicle comes to a complete stop is
braking distance. Average reaction
time is about three-fourths of a
second. But that is only an average.
It might be less with one driver and
as long as two or three seconds or
more with another. Age, physical
condition, alertness, coordination
and eyesight all play a part. Braking
distance will vary based reaction

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
Driving and Operating 135
time, the amount of force applied to
the brake pedal and the speed of
the vehicle.
When driving, bear the stopping
distance in mind. Maintain a speed
and headway distance that allow
you to stop safely even if a hazard
occurs.
Overriding Accelerator with
Brakes
In the unlikely event the accelerator
pedal becomes stuck, apply the
brakes firmly and steadily to reduce
engine power and bring your vehicle
to a safe stop. Turn the engine off,
move the selector lever to the“P”
(Park) position, and apply the
parking brake. In a safe location,
inspect the accelerator pedal for any
interference and remove the item
causing the interference, if any is
found. If none is found and the
condition persists, have your vehicle
towed to the nearest authorized
dealer.
Braking Techniques
For the most effective braking and
for maximum life from brake system
components, follow these
suggestions when possible:
. Apply the brakes gradually as
road and load conditions permit.
Reduce pedal pressure as
speed drops so that a very light
pressure is used at the end of
the stop.
. Do not pump the brake pedal as
this will only deplete the vacuum
reserve or the hydraulic brake
booster (HBB) accumulator
reserve.
. To get maximum braking while
maintaining vehicle control, use
a "squeeze" braking technique.
Do this by pushing on the brake
pedal with steadily increasing
pressure. If possible, steer
around obstacles when there is
not enough room to stop. Brake System Warning LightCaution
If brake low vacuum warning light
(4500HD, 4500XD models), brake
booster warning light (5500HD,
5500XD models), or brake system
warning light comes on during
operation, have brake system
checked immediately.
Refer to Warning Lights, Gauges,
and Indicators 056.
When the Brakes Do Not Work
{Warning
It is very dangerous to suddenly
pull the parking brake lever all the
way while moving at high speed.
Reduce speed first by shifting
down and then gradually pull the
parking brake lever.
You and others could be seriously
injured.

Chevrolet Low Cab Forward 5.2L Diesel Engine 4500 HD/XD/5500 HD/XD
Owner Manual (GMNA-Localizing-U.S.-13337621) - 2020 - crc - 12/5/18
Driving and Operating 137
Warning (Continued)
should overheat, as indicated by
the engine coolant temperature
gauge, immediate action is
required to correct the condition.
Continued operation of the
engine, even for a short time, may
result in a fire. Do not engage the
exhaust brake while the engine is
idling as this may cause engine
overheating.
The diesel particulate filter (DPF)
may automatically start
regeneration when the vehicle is
stopped and parked with the
engine running. To prevent a fire,
make sure there is no flammable
material near the muffler, DPF,
and exhaust pipe. Be careful not
to get burned by hot exhaust
gases.
You and others could be seriously
injured.Do Not Forget to Release the
Parking Brake
Pulling away with the parking brake
still applied can damage the brake
system.
Before pulling away, make sure the
parking brake is not set by checking
that the parking brake indicator light
is not on.
Be Sure to Have the Engine
Running When the Vehicle is
Moving
{Warning
When the engine is not running,
the power steering system does
not work so the steering wheel is
hard to turn. Also, the brake
booster does not work so there is
little braking ability. If you coast
down a slope without the engine
running, you would not be able to
properly control the vehicle and
could have a crash.
Parking, or Leaving
Driver
’s Seat
{Danger
It can be dangerous to get out of
your vehicle if the selector lever is
not fully in "P" (Park) or the
parking brake is not applied all
the way. Your vehicle can roll or
move suddenly.
To be sure your vehicle will not
move, even when you are parking
on level ground, follow the steps
below. (If you have to park on a
hill, also turn your front wheels so
the vehicle will roll away from
traffic.)
You and others could be seriously
injured or killed.
1. Hold the regular brake pedal down with your right foot and
apply the parking brake all the
way before shifting the
transmission. Follow the
Parking Brake instructions in
this manual for your vehicle.