Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
11254764) - 2018 - crc - 12/5/16
196 Driving and Operating
Overdrive Off Indicator Light
Indicator lightFunction Usage conditions
Goes Off. 6-Speed (4-speed + overdrive) automatic
change (Overdrive ON). Use under normal driving conditions.
Comes On. 4-speed automatic change, but no change to
overdrive (overdrive OFF). Used when a light engine brake is required.
Doing so will reduce the number of gear
changes making the ride smoother on roads
that have many hills.
. During cold weather, the
transmission may not shift to the
5th or 6th gear (overdrive) until
the engine warms up.
. Even if the engine is stopped
with the overdrive OFF, the
overdrive will be ON the next
time the engine is started.
Brakes
Antilock Brake
System (ABS)
Wheels may be locked and slip
during sudden braking or braking on
a slippery road surface such as a
snowy road. ABS is a device to
prevent the wheels from locking by
detecting a slippery condition during
braking and securing the directional
stability and handling stability of the
vehicle. ABS only assists in limited
road conditions and will not prevent
an accident if you exceed safe
driving speeds for road conditions.
Always drive safely.
{Warning
The braking distance on slippery
road surfaces is longer than that
on a normal dry paved road even
with an ABS-equipped vehicle. In
addition the braking distance can
be slightly longer in deep snow
and on a gravel road when ABS
is activated. Therefore, always
keep in mind the road condition
and tire condition (type of tires
and worn condition), observe safe
driving habits and drive the
vehicle while keeping a proper
distance between vehicles.
(Continued)
Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
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Driving and Operating 197
Warning (Continued)
ABS does not prevent accidents if
you do not drive safely. Drive the
vehicle at a safe speed.
Install tires of the specified size,
same brand and same tread
design (including winter tires) on
all wheels. If different tires are
installed, the braking distance
becomes longer and directional
control stability of the vehicle
decreases. This is very
dangerous.
Steering during sudden braking
(when the ABS is working) will
feel slightly different than it does
when the brakes are not applied.
Operate the steering wheel
carefully keeping this in mind.
Driving in sand or on a muddy road
may adversely affect the brakes and
ABS sensors. Wash the vehicle to
remove sand and mud after
operating the vehicle in sandy or
muddy conditions. Before washing the vehicle, provide
necessary protection to prevent
water from being splashed on the
ABS components (sensors and
actuators). Especially when using
high-pressure washing, be careful
not to allow water to be directly
sprayed onto the ABS components
and their harness connectors.
These are not signs of ABS
malfunction:
.
Soon after you start the engine
and the vehicle starts moving,
the sound of motor or valve
working may be heard from the
rear of the vehicle or underside
of the cab. This sound is from a
self-check by the ABS system
and is normal. In addition, you
may also feel some vibration if
the brake pedal is pressed at
this time.
. When ABS is operating,
vibration is felt on the brake
pedal and steering wheel and
you may hear the system
operating. This is normal when
ABS is properly operating. .
The exhaust brake may release
when ABS is activated and the
exhaust brake is in operation.
. ABS is more likely to be
activated when the brake is
applied during cornering or
driving over a bump. This is
because inside wheels or
wheels that have gone over a
bump tend to lock.
. ABS is not activated immediately
after starting the vehicle. It is
activated only when the vehicle
speed reaches approx. 10 km/h
(6 MPH). ABS operation is
inactive when the vehicle speed
reduces to approx. 5 km/h
(3 MPH).
Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
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198 Driving and Operating
ABS Operation Indications and
Signs
ABS warning light
Operation Indications of ABS
When the engine control switch is
placed into the "ON" position, the
ABS warning light comes on and
then goes out in approx. 3 seconds.
The ABS is normal if the warning
light goes out.
Operation Signs of ABS
When ABS is activated, slight
vibration is generated on the brake
pedal (hydraulic brake model) and
steering wheel, and an operating
sound can be heard from the ABS
equipment.
If the ABS warning light does any of
the following, the ABS may be
faulty. Please contact the nearest
dealer. ‐
If the ABS warning light comes
on during driving
‐ The light does not come on when
the engine control switch is
placed into the "ON" position
See Antilock Brake System
(ABS) Warning Light 077.
Even if a problem has occurred with
the ABS, the regular brakes will still
work normally. However, ABS will
not operate.
Precautions for Driving an
ABS-Equipped Vehicle
ABS is not a device that enables
driving and stopping under
conditions exceeding safe driving
limits. Always drive safely.
{Warning
When braking suddenly, continue
pressing brake pedal hard so that
the ABS can take effect. (Continued)
Warning (Continued)
When braking suddenly, do not
pump the brakes (pushing and
releasing the brake pedal little by
little). Pumping brakes will
increase the braking distance.
The braking distance on slippery
road surfaces is longer than that
on a normal dry paved road even
with an ABS-equipped vehicle.
When ABS is activated in the
following road surface conditions,
the braking distance may be
slightly longer compared to that of
vehicles not equipped with an
ABS. Therefore, always be aware
of the road and tire condition (tire
type and wear condition), observe
safe driving habits and drive the
vehicle while keeping a safe
following distance.
‐ When driving on a gravel
road, or a road with a deep
snow covering.
‐ When tire chains are used.
(Continued)
Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
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Driving and Operating 199
Warning (Continued)
‐When driving over road
joints or bumps such as
light reflectors on the road.
‐ When driving on a bumpy
road, stone-paved road or
track.
‐ When driving over an iron
plate or manhole lid.
ABS does not work for wheel skid
during a standing start,
acceleration and cornering which
do not involve braking. On a very
slippery icy road, tires may lose
grip and steering wheel operation
may not be able to control the
vehicle's direction, resulting in
very unstable driving. Always
drive the vehicle observing a safe
speed well matched with both
road surface and tire conditions,
and avoid sudden braking.
If powerful engine braking is
applied on a very slippery icy
road, the drive wheels may be (Continued)
Warning (Continued)
locked (the ABS then does not
work), resulting in loss of vehicle
control.
When ABS is activated, a slight
vibration (especially when the
road surface is different between
right and left wheels) and pulling
may be felt on the brake pedal
and steering wheel. In addition,
an operating sound is produced
from the ABS actuators. This
does not indicate any abnormal
condition. Stay calm and operate
the steering wheel properly.
Electronic Braking force
Distribution (EBD)
EBD is a function that uses the ABS
to distribute braking force ideally
between the front and rear wheels
in order to compensate for changes
in load conditions or any shift of the
load due to acceleration or
deceleration, thus preventing
premature locking of the rear
wheels.
{Warning
If a problem should occur with the
EBD function, the ABS warning
light and the brake system
warning light will come on
simultaneously.
The rear wheels will lock more
easily if there is a problem with
the EBD function. Have it
checked and serviced at the
nearest dealer as soon as
possible. You and others could be
seriously injured.
When the EBD operates, the brake
pedal may push back slightly or you
may hear a sound similar to that
generated by the ABS when
operational. Neither of them
indicates any abnormal condition.
Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
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202 Driving and Operating
Even if the selector lever is placed
in the N position, the exhaust brake
does not disengage until the engine
is warmed up if the warm-up system
is on.
Conditions for Inoperable Exhaust
Brake
Under the following conditions, the
exhaust brake does not engage
even if the exhaust brake indicator
light comes on:
.The accelerator pedal is
pressed.
. The selector lever is in the N
position.
. The vehicle is traveling at
5 km/h (3 MPH) or lower speeds.
If your vehicle is equipped with an
anti-lock brake system (ABS), the
exhaust brake may disengage
during ABS operation even when
the exhaust brake switch is in the
ON position and the exhaust brake
indicator light is on. The exhaust
brake may disengage temporarily as
the vehicle passes over a bump
even when the brake pedal is not
pressed. It is advisable to operate the
exhaust brake when descending a
slope or when stop and go driving is
involved.
The selection of transmission gears
and engine speed when operating
the brake system is important. The
exhaust brake is more effective in
the lower gears and at the higher
engine speeds. See
Exhaust Brake
Light 078.Cruise Control
The cruise control function allows
you to drive the vehicle at a
constant speed without operating
the accelerator pedal. Use this
function when the vehicle speed is
between 40 to 160 km/h (25 to 100
MPH). This function should only be
used when driving without frequent
starts and stops.
{Warning
Cruise control can be dangerous
where you cannot drive safely at
a steady speed. Do not use
cruise control on winding roads or
in heavy traffic. You and others
could be seriously injured.
Cruise control can be dangerous
on slippery roads. On such roads,
fast changes in tire traction can
cause needless wheel spinning,
and you could lose control. Do
not use cruise control on slippery
roads. You and others could be
seriously injured.
Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
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216 Driving and Operating
When Operating the PTO
For operation of special equipment,
see the manufacturer’s instructions.
Installations, or alterations to the
original equipment vehicle or
chassis, as manufactured and
assembled by General Motors, are
not covered by this warranty. The
body company, assembler,
or equipment installer is solely
responsible for warranties on the
body or equipment and any
alterations to any of the parts,
components, systems,
or assemblies installed by GM.
Examples include, but are not
limited to, special body installation,
such as recreational vehicles, the
installation of any non-GM part,
cutting, welding, or the
disconnecting of original equipment
vehicle or chassis parts and
components, extension of the
wheelbase, suspension, and
driveline modifications, and axle
additions. The engine control module (ECM)
has the ability to accommodate one
of three different PTO modes. Each
mode can be programmed to
accommodate many PTO devices.
Optional PTO switches are available
from your dealer to ease installation
of a PTO.
The optional PTO main switch and
PTO engine speed control switch
can be used increase the engine
idle r/min without additional
programming. Pressing the PTO
main switch once will activate the
PTO mode and raise the idle up
speed up to the preset 800 r/min.
Once in PTO mode the PTO engine
speed control switch can be used to
adjust the idle speeds between the
preset 1,300 and 1,700 r/min.
Moving the selector lever from park
or neutral, applying the brake pedal
or releasing the parking brake will
cancel PTO mode and return the
engine idle speed to normal. For
additional details about PTO
programming, contact your dealer.
Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
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Vehicle Care 217
Vehicle Care
General Information
General Information . . . . . . . . . . 218
California Proposition65 Warning . . . . . . . . . . . . . . . . . 218
California Perchlorate Materials Requirements . . . . . 218
Accessories and Modifications . . . . . . . . . . . . . . . . 218
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 218
Cab Tilting . . . . . . . . . . . . . . . . . . . . 220
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . 222
Engine Cover . . . . . . . . . . . . . . . . . 222
Engine Oil . . . . . . . . . . . . . . . . . . . . 223
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . . . 229
Engine Air Cleaner/Filter . . . . . . 231
Engine Coolant . . . . . . . . . . . . . . . 231
Engine Overheating . . . . . . . . . . 237
Power Steering Fluid . . . . . . . . . 240
Washer Fluid . . . . . . . . . . . . . . . . . 241
Brakes . . . . . . . . . . . . . . . . . . . . . . . 242
Brake Fluid . . . . . . . . . . . . . . . . . . . 246
Battery . . . . . . . . . . . . . . . . . . . . . . . . 247
Fuel Filter . . . . . . . . . . . . . . . . . . . . 248 Rear Axle (Gear Oil Viscosity
Chart) . . . . . . . . . . . . . . . . . . . . . . . 249
Rear Axle (Oil Level Check) . . . . . . . . . . . . . . . . . . . . . . 249
Noise Control System . . . . . . . . 250
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . . . 251
Wiper Blade Replacement . . . . 252
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . . . 254
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . 254
Headlamps and Front Turn Signal . . . . . . . . . . . . . . . . . . . . . . . 257
Roofmarker Lamps . . . . . . . . . . . 261
Sidemarker Lamps (Including Turn Signal and Cornering
Lamps) . . . . . . . . . . . . . . . . . . . . . . 261
Taillamps, Turn Signal, Stoplamps, and Back-Up
Lamps . . . . . . . . . . . . . . . . . . . . . . 263
License Plate Lamp . . . . . . . . . . 263
Interior Lamps . . . . . . . . . . . . . . . . 264
Electrical System
Electrical System Overload . . . 264
Wheels and Tires
Wheels and Tires . . . . . . . . . . . . . 272 Tire Pressure . . . . . . . . . . . . . . . . . 284
Tire Rotation . . . . . . . . . . . . . . . . . 284
If a Tire Goes Flat . . . . . . . . . . . . 287
Jump Starting
Jump Starting - North
America . . . . . . . . . . . . . . . . . . . . . 287
Towing the Vehicle
Towing the Vehicle . . . . . . . . . . . 291
Appearance Care
Exterior Care . . . . . . . . . . . . . . . . . 293
Interior Care . . . . . . . . . . . . . . . . . . 299
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Vehicle Care 219
Warning (Continued)
vehicle or its equipment. If you
have any questions about
carrying out some service, have
the work done by a skilled
technician.
To prevent personal injury, keep
hands, tools and clothing clear of
the engine cooling fan when the
engine is running.
The engine, exhaust pipe and
radiator will be hot immediately
after the vehicle is driven. Be
careful around these parts to
prevent burns. Perform all checks
when the engine is cold.
Do not perform work near an
open flame or other heat sources.
Do not let the engine run in poorly
ventilated garages or sheds. This
could cause carbon monoxide
poisoning.(Continued)
Warning (Continued)
Performing maintenance work on
a truck or chassis can be
dangerous. In trying to do some
jobs, you can be seriously injured.
Do your own maintenance work
only if you have the required
know-how and the proper tools
and equipment for the job. If you
have any doubts, contact your
dealer.
You and others could be seriously
injured.
Pull firmly on the parking brake
lever and move the selector lever to
"P" and make sure the shift indicator
displays "P".
Make sure to turn off the engine and
remove the key from the engine
control switch before performing any
checks.
Select a place with a solid and level
surface to perform the checking and
maintenance work. Make sure to chock the wheels. It would be very
dangerous if the vehicle started
to move.
When performing work on the
electrical system, begin by turning
the engine control switch to the
"LOCK" position, wait at least
3 minutes, and then disconnect the
negative cable from the negative
terminal on battery. If the negative
cable is disconnected within
3 minutes, the engine control
module may malfunction.
When working on the fuel line or
fuel filter, remove the fuel tank filler
cap. The fuel system is under
pressure and the fuel will overspill
unless the pressure is relieved,
possibly leading to combustion or
a fire.
Do not make engine adjustments
yourself. Be sure to consult your
dealer.
Use only appropriate tools.
Oils, brake fluid and engine coolant
have lubrication, cooling and rust
prevention functions. If these liquids
deteriorate through loss or