brakes CHEVROLET LOW CAB FORWARD 2018 Owner's Guide

Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
11254764) - 2018 - crc - 12/5/16
Driving and Operating 189
accelerator pedal the engine may
automatically shift down in
accordance to the current speed
(shifts to a lower speed gear),
increasing the engine speed and
increasing vehicle speed.
Driving Uphill or Downhill
Uphill driving:
With the selector lever in D, if you
press down on the accelerator
pedal, kickdown (change to a low
speed gear) may operate causing
the engine revolutions to suddenly
increase (increasing the speed).
Driving for a prolonged duration on
an uphill road with the selector lever
in D may cause the automatic
transmission fluid to overheat.
Drive with the overdrive off switch
ON to keep the engine revolutions
constant to enable smoother driving
with fewer changes in engine
revolutions.Driving conditions Selector lever position
Normal uphill road D (overdrive off switch ON)
Steep uphill, steep slope, mountain
road with many sharp curves 2 or 1
Long uphill road 2
Downhill driving:
Do not overuse the foot brake. This
will cause the brakes to overheat,
reducing their effectiveness. On
long downward slopes or sharp
downhill sections of road, use the
engine brake together with the foot
brakes to control the speed.
When the selector lever is in the D
position, you can drive with the
overdrive off switch ON to allow a
gentle engine brake to be applied.
Push the overdrive off switch to the
ON position at speeds below
101 km/h (63 MPH) to increase
engine braking action when
traveling downgrade.
You can increase engine braking by
driving with the selector lever in the
2 position. To apply a stronger engine brake on
sharp downhill sections, shift the
selector lever to the 1 position when
required.
See
Control of a Vehicle 0122.
Driving at Low Speeds for
Sustained Periods
Any low speed applications such as
sweeper, road marking machinery,
trash collectors, highway striping or
moving, etc. require the following
treatment to prevent the automatic
transmission fluid (ATF) from
overheating:
Select 1 position during low speed
operation under 18 km/h (11 MPH).
Select 2 position during low speed
operation under 36 km/h (22 MPH).

Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
11254764) - 2018 - crc - 12/5/16
Driving and Operating 193
Actions that Can Lead to a Breakdown with an Automatic Transmission
Actions that can lead to a breakdownBreakdown symptoms
Stopping the vehicle on an uphill road with the selector lever in a position
other than R, N, or P, the accelerator pedal pressed, and the brakes not
applied. The transmission fluid overheats.
Continuously pressing the accelerator pedal and brake pedal at the same
time while the vehicle is in a position other than N or P.
Placing the selector lever into any gear with the accelerator pedal pressed
and the engine speed high. The transmission gears are
overloaded.
Placing the selector lever into P before the vehicle has completely stopped. The parking mechanism will be
damaged.
Turning off the engine control switch while driving. The transmission is not properly
lubricated.
Driving with the selector lever in the N position on a long downward slope
(this is dangerous due to the lack of engine brake).

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.-
11254764) - 2018 - crc - 12/5/16
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.-
11254764) - 2018 - crc - 12/5/16
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.-
11254764) - 2018 - crc - 12/5/16
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

Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
11254764) - 2018 - crc - 12/5/16
242 Vehicle Care
Follow the instructions provided with
the windshield washer fluid
regarding the ratio for mixing with
tap water.
Poor quality products, engine
coolant, and soapy water must not
be used. Failure to observe this
precaution can result in nozzle
blockage or damage to painted
surfaces.
The washer should never be used
while the tank is empty. Operating
the washer with the tank empty can
result in motor damage.
Brakes
For the most effective braking and
for maximum life from brake system
components, follow these
suggestions:
.Keep any obstructions from
interfering with brake pedal
travel.
. Keep tires properly inflated.
Improperly inflated tires can
reduce the efficiency of the
brakes. Follow the recommendations for
brake checks in the Maintenance
Schedule.
GM replacement brake lining
material is recommended for this
vehicle to maintain the balance
between front and rear brake
performance. GM replacement
brake parts have been carefully
selected to provide the proper brake
balance for purposes of both
stopping distance and controllability
over the full range of operating
conditions. Installation of front or
rear brake lining material with
performance different from that of
the replacement parts
recommended for this vehicle can
change the intended brake balance
of this vehicle.
Checking the Brake Electric
Vacuum Pump (4500HD/
4500XD Series)
1. Turn the engine control switch
to the "ON" position (do not
start the engine), and press the
brake pedal several times. 2. Check for the noisy sound of
the electric vacuum pump
inside the instrument panel at
the same time as vacuum
warning buzzer sound, and
check that the brake low
vacuum warning light
comes on.
3. Then, start the engine. The main vacuum pump driven by
the engine will start running.
If the electric vacuum pump
operation (noisy sound) and
the vacuum warning buzzer
stop, and the brake low
vacuum warning light goes off
thereafter, the operation is
normal.
4. If you cannot hear the noisy sound or the noisy sound stays
on all the time, have the
vehicle inspected by the
nearest dealer immediately.Hydraulic Brake Booster (HBB)
The 5500HD, 5500XD models are
equipped with an HBB system. HBB
is a brake booster device that

Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
11254764) - 2018 - crc - 12/5/16
Vehicle Care 243
utilizes hydraulic pressure from the
HBB pump integral with the power
steering pump.
If the brake booster warning light
comes on or a warning buzzer
continues to sound, there may be a
problem with the HBB.
If this warning light comes on while
driving, immediately stop your
vehicle at a safe place well clear of
traffic and promptly contact the
nearest dealer for inspection.
Hydraulic brake booster (HBB)
characteristics
In the 5500HD, 5500XD models, an
unusual sound from under the
instrument panel may be heard from
the hydraulic system while brakes
are used. It does not mean trouble.
It is not a sign of malfunction.
If you pump the brakes with the
engine off, a squeaking sound can
be heard. This comes from the
auxiliary accumulator. It is not a
malfunction. With the engine
running, a similar sound can be
heard during sudden braking.Another characteristic of the HBB
system is that the brake pedal may
be pressed easily to the floor with
the vehicle at a stop. This is not a
sign of malfunction.
When the engine is running, the
system automatically charges the
accumulator whenever pressure has
been reduced after braking. Auto
charge may be activated without
braking, depending on temperature
changes in the accumulator. During
auto charge, a hissing and clicking
sound can be heard. This is not a
malfunction.
With the engine running, a booming
sound can be heard during hard
braking. This comes from the
brake-fluid pump. It is not a
malfunction.
Applying continuous hard braking
for a long time will lead to
considerable temperature rise in the
HBB pump. Such overworking of the
brakes is best avoided.
Vacuum or hydraulic power
assisted brakes
If the engine stops, do not pump the
brakes. The system is designed to
stop the vehicle with reserve power
assist if the brake pedal is held
down. This reserve is greatly
reduced each time you apply and
release the brakes. If, when you
turn the steering wheel during
braking, the vehicle does not turn,
release some pressure from the
brake pedal.
In a Vehicle Equipped with an
HBB, Do Not Keep the Brake
Pedal Pressed for an Extended
Period
Caution
Failure to follow the above
instruction will cause the oil inside
the HBB oil pump to get very hot.
This could damage the HBB tank
and deteriorate seals and also
could cause damage to the HBB
oil pump, HBB unit and/or HBB
(Continued)

Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
11254764) - 2018 - crc - 12/5/16
244 Vehicle Care
Caution (Continued)
hosing. Eventual leakage of HBB
oil, sudden increase in brake
pedal resistance and fire could
unexpectedly result in an
accident.
Hydraulic Brake Booster (HBB)
Fluid (5500HD/5500XD Series)
The HBB system has been
designed to use Dexron VI ATF
fluid. If any other fluid is used with
this system, rubber components
may be damaged, oil may leak and
the system may malfunction. It is
important to remember that the fluid
used in the hydro-booster is
completely different in
characteristics from the brake fluid
used in the master and wheel
cylinders.
If hydro-booster fluid and brake fluid
from the master cylinder are
mistakenly mixed together and
used, rubber components will
deteriorate as a result of insufficient
lubrication. Any resultant oil leakage or system malfunction can in turn
lead to dragging brakes or other
major brake problems. As such,
mixing of these two fluids can
ultimately lead to vehicle fire or
other serious accidents.
When the pump operates while the
engine is running, the fluid in the
hydro-booster will become hot.
During normal braking, the
temperature in piping and within
the hydro-booster can rise above
100 °C (212 °F). For this reason,
special care will be required when
working with hydro-booster
components. If the hydro-booster is
to be removed from the vehicle,
shut off the engine and then allow at
least 30 minutes for it to cool down
before beginning this operation.
Even when the engine is stopped,
the hydro-booster's accumulator will
remain in a highly-pressurized
condition for a significant period of
time. Before removing the
hydro-booster or piping from the
vehicle, stop the engine and press
the brake pedal at least 10 times in
order to lower the accumulator
pressure to atmospheric pressure.This is of particular importance
when removing components such
as the accumulator or pressure
switch from the hydro-booster.
If these operations are attempted
while the accumulator is still at a
high pressure, hydro-booster fluid
may spray out.
Checking the Hydro-booster Fluid
Level
Check the hydro-booster fluid level
and change the fluid according to
the Maintenance Schedule.
The hydro-booster fluid level is
correct if it is between the "MAX"
and "MIN" lines. If the level is too

Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
11254764) - 2018 - crc - 12/5/16
246 Vehicle Care
If your vehicle's brakes squeak
during normal driving or braking, the
cause may be one of the following.
‐Brake pad wear
Brake pads are about to wear
out. If this happens, have your
vehicle inspected at the nearest
dealer as soon as possible.
‐ Adherence of sand, grit or mud
If sand, grit or mud adheres to
the brakes, a screeching sound
may be emitted upon contact with
rotating components. If this
happens, wash the vehicle to
remove all such adhering matter.
If cleaning alone does not
eliminate the squeaking sound,
have your vehicle inspected at
the nearest dealer.
Brake Hoses and Pipes
Inspection
With the steering wheel turned fully
to the left, check the left front brake
hose and pipe visually and by
touch, making sure that they are
free of scratches, cracks and
bulging. Also make sure that the hose and pipe do not interfere with
any chassis part or wheel, and that
their joints are not leaking and are
free of any type of damage. Check
the right front brake hose and pipe
in the same way. The rear left and
right brake hoses and pipes should
also be checked in the same
manner.
Disc Brakes and Drum Brakes
If the brake pads and shoe linings
wear out beyond their usable limit,
not only will the brake performance
be impaired, but brake components
could also fail.
{Warning
Do not drive with brake pads and
shoe linings worn out beyond the
limit. Excessively worn brake
pads and shoe linings may cause
breakdown of brake components
and poor braking performance.
You and others could be seriously
injured.
Caution
The pad has an embedded wear
indicator. A squeaking noise from
the indicator means that the pad
is approaching the usable limit.
If the squeaking noise from the
indicator can be heard, contact
the nearest dealer for inspection
or replacement.
Brake Fluid
Checking the Brake Fluid
Level