maintenance CHEVROLET LOW CAB FORWARD 2020 Owner's Guide

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
Vehicle Care 231
Vehicle Checks
Doing Your Own
Service Work
Precautions for Checking and
Adjustments
Your authorized dealer has trained
technicians and genuine parts to
service your vehicle properly. For
expert advice and quality service,
see your authorized dealer.
{Warning
To help avoid personal injury, take
care when doing any
maintenance or making any
check or repair. Follow
manufacturer's instructions for all
materials used during service and
maintenance of this vehicle.
If used or handled improperly,
they may be hazardous. Improper
or incomplete service can also
affect the vehicle and result in(Continued)
Warning (Continued)
personal injury, or damage to the
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

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
232 Vehicle Care
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 orcontamination, it will cause a
decline in the performance of the
parts and such problems as seizure
or malfunctioning. Replenish or
change these liquids when
performing the checks (daily and
periodic checks) as required by the
relevant regulations or in
accordance with the Maintenance
Schedule (when either the specified
driving distance or period of time,
whichever comes first, has expired).
Confirm that all systems and
components are normal after
performing the work.
Do not leave the removed parts or
tools in the engine compartment.
They could damage the equipment if
caught in the belts or other moving
components.
Dirty water, dirt and other impurities
seriously impair the effectiveness of
the oil, grease and fluids, and
damage the parts. Exercise all due
caution to prevent waste or other
refuse from coming in contact with
parts or materials that have been
removed when changing or
replenishing them.Do not step on the engine or climb
onto it. You could cause an engine
failure by, for example, damaging
the cylinder head cover or various
connectors.
Electric Welding
Careless electric welding of vehicle
parts can cause welding current to
flow back through the vehicle’s
ground circuit and damage electrical
and electronic parts so that they do
not function normally. Whenever
electric welding is necessary,
consult your dealer.

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
236 Vehicle Care
and the oil should be changed
regularly according to the
Maintenance Schedule.
The engine oil performs the
following important functions:
.It prevents engine parts from
becoming worn.
. It cools engine parts.
. It cleans engine parts.
. It seals the combustion
chambers and prevents rust.
Replace the engine oil at regular
intervals.
When particulate matter (PM) has
accumulated to a preset level in the
diesel particulate filter (DPF), the
filter is automatically regenerated
through combustion. To make this
regeneration (combustion) possible,
a small amount of fuel is injected
into the engine combustion chamber
after firing. This causes fuel to
gradually become mixed with the
engine oil, and the engine oil level
may rise beyond the original level.
This does not indicate a malfunction
of the engine.Access to the Engine
Single Cab Model
Access to the engine oil dipstick is
located on the engine left side after
tilting the cab. See Cab Tilting
0 233.
Crew Cab Model
The engine oil dipstick is under the
engine inspection sub cover located
beneath the driver's seat.
Checking the Engine Oil Level
Press the engine oil level check
switch. If engine oil level is low the
red oil pressure warning light will
turn on. If the engine oil level is
above the "OK", the green oil level
indicator will turn on.
The oil level varies while the engine
is running, right after it is stopped,
and on sloping ground. When
checking the oil level, be sure the
vehicle is on level ground while the
engine is cool.

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
238 Vehicle Care
Caution
When adding oil, be careful not to
spill any, but keep a workshop rag
handy just in case there are any
spills. If any oil should spill onto
the engine, carefully wipe it away.
If this precaution is not taken, the
spilled oil could ignite and a fire
could spread.
Do not leave flammable items,
such as rags or gloves, in the
engine compartment. They could
cause a fire. You and others could
be seriously injured.
Engine oil lubricates and cools the
engine's internal components. The
quality of the oil is degraded and the
quantity of oil is reduced by
evaporation, discharge and
combustion during the operation of
the engine. Continually using the
same oil without checking the level,
or without replenishing and
changing it could cause seizure or
damage to the engine. Prevent dirt from entering the filler
port when adding the oil. If foreign
matter mixes with the oil, it could
damage the engine.
Adding oil above the "FULL" mark
on the oil dipstick could result in
faulty engine operation. Be sure to
check the oil level by using the oil
dipstick.
Failure to use the recommended
engine oil could result in engine or
DPF breakdown, or in poor fuel
efficiency. Be sure to use the
recommended engine oil.
Choosing the Right Quality Oil
If you do not use the oil intended for
a vehicle equipped with a Diesel
Particulate Filter (DPF), both the
engine and the DPF may break
down and fuel economy may
decrease. Be sure, therefore, to use
the oil intended for vehicles
equipped with DPF.
GM recommends engine oil that
supports DPF (Low ash oil). Use of
engine oil that does not support low
ash will increase the PM produced
by engine combustion.Consequently, the maintenance
interval of the DPF filter will be
reduced.
Oil Identification Logo
A logo (symbol) is used on most oil
containers to help you select the oil
you should use. The top portion of
the logo shows the oil quality by API
designations such as CK4 or others.
The center portion of the logo
shows the SAE viscosity grade,
such as SAE *W-40 (* indicates
viscosity on the low temperature
side). You should look for this logo
on the oil container, and use ONLY
oil containing the logo.

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
Vehicle Care 239
Change Intervals
The oil and oil filter change intervals
for your engine are based on the
use of recommended oil quality and
viscosity, as well as high-quality
filters such as genuine GM oil filters.
Using oil other than recommended,
or oil and filter change intervals
longer than recommended, could
reduce engine life. Damage to
engines due to improper
maintenance or use of incorrect oil
quality and/or viscosity is not
covered by the new vehicle
warranty.
Your engine was filled with a
high-quality engine oil when it was
built. You do not have to change this
oil before the first recommended
change interval. Oil and filter
change intervals depend on how
you use your vehicle. For
information on the proper oil and
filter change intervals. See
Maintenance Schedule0317. Engine Oil Additives
Engine oils contain a variety of
additives. Your engine should not
need any extra additives if you use
the recommended oil quality and
change intervals.
{Warning
Used engine oil contains harmful
contaminants that have caused
skin cancer in laboratory animals.
Avoid prolonged skin contact.
Clean skin and nails thoroughly
using soap and water–not mineral
oil, fuels or solvents. Launder or
discard clothing, shoes or rags
containing used engine oil.
Engine Oil and Gear Oil
Viscosity Charts
Select appropriate engine oil in
accordance with the table below.
It is also important to select the
viscosity appropriate for the
temperature at which your vehicle
operates. Use the following table for
making correct selections. Engine Oil
Engine oil viscosity (thickness) has
an effect on fuel economy and
cold-weather starting. Lower
viscosity engine oils can provide
better fuel economy; however,
higher temperature weather
conditions require higher viscosity
engine oils for satisfactory
lubrication.
When choosing an oil, consider the
range of temperature your vehicle
will be operated in before the next
oil change. Then, select the
recommended oil viscosity from the
chart.
Do not use any viscosity of oil not
recommended. Such oils could
cause engine damage.

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
240 Vehicle Care
This Engine Oil Viscosity Grade
Chart shows general information.
For this vehicle, oil with *W-40
viscosity is recommended.
Changing the Engine Oil and
Oil Filter
Engine oil and the oil filter are
important factors in engine
performance and lifespan. Be sure
to use only the specified oil and oilfilters. The engine oil level must be
checked and the oil should be
changed regularly according to the
Maintenance Schedule.
Use the indicated oil quantities only
as guidelines when changing the
engine oil. After changing the oil,
make sure the oil is at the required
level. See
Capacities and
Specifications 0349. Failure to use the recommended
engine oil could result in engine or
DPF breakdown, or in poor fuel
efficiency. Be sure to use the
recommended engine oil.
Engine oil change precaution:
.
When adding oil, remove the
dipstick.
. After adding oil, wait for at least
5 minutes before starting the
engine. Be sure to reinstall the
dipstick.
Discarded Parts, Oils and
Other Liquids
When changing oils, filters, engine
coolant or other liquids, be sure to
have a container ready in advance
for their disposal.
Use methods conforming to legal
requirements for discarding or
disposing of parts, oils, filters or
engine coolant after change or
replacement.
Do not dispose of used engine oil,
fuel or any other oil in a careless
manner such as pouring it on the
ground, into sewers, or into streams

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
Vehicle Care 243
.Dipstick H (HOT) —
Transmission fluid
temperature Approx. 70 -
80 °C (158 - 176 °F).
. The “C (COLD)” range on
the dipstick is a guide used
by your dealer for
specialized equipment used
to replace or service the
automatic transmission
fluid. When performing your
own inspections, always
use the “H (HOT)” range
after warming up the
vehicle.
The fluid must be hot to
ensure an accurate check.
The fluid level rises as
temperature increases.
6. If the fluid level is too low, add the specified fluid through the
dipstick guide tube. Also, check
whether there are no fluid
leaks.
7. Insert the dipstick securely into position.{Warning
Be extremely careful not to burn
yourself when checking the oil
level if the engine temperature is
high. Protect yourself with
gloves etc.
You and others could be seriously
injured.
Discarded parts, oil, grease and
fluids could have an adverse effect
on the environment. It is difficult to
dispose of these, so have your
dealer handle all checks and
replacements.
Engine Air Cleaner/Filter
Air Cleaner
Using a clogged air cleaner element
not only reduces engine output but
also causes increased fuel
consumption and an increased DPF
regeneration frequency. Be sure to use a genuine air cleaner
element. If a different air cleaner
element is used, it may cause the
sensor to output a wrong signal.
See
Maintenance Schedule 0317.
Air Cleaner Indicator Light
When the air cleaner indicator light
comes on, check the air cleaner
element. If the air cleaner element is
clogged, replace the air cleaner
element.
See Vehicle Messages 074.
See Maintenance Schedule 0317.
Engine Coolant
Protection of Engine Against
Overcooling
Overcooling of the engine not only
accelerates wear of the vital engine
parts but also hurts fuel economy.

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
244 Vehicle Care
Engine Coolant in Cold
Weather
To prevent the engine damage due
to freezing of the engine coolant,
mix the coolant and water at the
ratio of 50/50.
Replace rubber hoses whenever
they crack or are damaged; even
minor cracks allow engine coolant
solution to leak.
{Warning
If your engine cooling system
overheats, seeEngine
Overheating 0249. Continued
operation of the engine even for a
short time may result in a fire and
the possibility of personal injury
and/or severe vehicle damage.
You and others could be seriously
injured.
Your vehicle has an engine coolant
recovery system, expansion bottle
and/or an engine coolant reserve
tank system. Engine coolant in the
system expands with heat and overflows into the reserve tank.
When the system cools, engine
coolant is drawn back into the
radiator.
The engine cooling system has
been filled at the factory with a
quality engine coolant. It is
important to use proper engine
coolant to prevent damage to
engine cooling system components.
The engine cooling system is
designed to use engine coolant
rather than plain water. See
Recommended Fluids and
Lubricants
0339.
See the Maintenance Schedule to
find out when the engine coolant
must be replaced. Note that
changing the engine coolant is
needed to replenish the rust
inhibitors to make certain that all
parts of the engine cooling system
work well.
{Warning
Check, replenish or change the
engine coolant only after the
engine has sufficiently
cooled down.
Do not loosen or remove the cap
of the radiator or engine coolant
reserve tank cap when the engine
coolant is still hot. Hot vapor or
boiling water may burst out and
cause a burn.
When removing the radiator cap
or engine coolant reserve tank
cap, use a thick cloth to cover the
cap and turn it slowly.
Engine coolant is toxic and must
not be ingested. If the engine
coolant is mistakenly ingested,
seek prompt medical attention.
If the engine coolant gets in your
eyes, rinse your eyes immediately
with a large amount of water for
15 minutes or longer. Also, if your (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
252 Vehicle Care
Power Steering Fluid
The power steering fluid level must
be checked and it must be changed
according to the Maintenance
Schedule. SeeMaintenance
Schedule 0317.
When replenishing power steering
fluid or flushing the power steering
system, always use ATF
(Dexron
®-VI). Failure to use the
proper fluid may damage the power
steering system seals and hoses,
leading to fluid leakage.
Checking the Power Steering
Fluid Level
The fluid level is correct if it is
between the “MAX”and“MIN” lines
on the power steering fluid tank.
If the level is lower that the “MIN”
line, add fluid up to the “MAX”line.
The reserve tank is located at the
rear of the engine compartment on
the right. When you have finished
checking the fluid level, securely
reinstall the cap and cover.
{Warning
Before adding fluid, clean the
area around the cap and pour
fluid from a clean jug or filler.
Foreign matter getting in the tank
may cause power steering system
failure.
Do not mix the recommended
power steering fluid with fluids of
other brands. Due to chemical
reactions, any mixture of
differently branded fluids may
cause failure of the system.
You and others could be seriously
injured.
Washer Fluid
Windshield Washer Fluid
The windshield washer is equipped
on the windshield wiper arm.
Check the level of fluid in the
windshield washer fluid tank. In
addition, spray windshield washer
fluid and operate the windshield
wipers to check for any areas not

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
254 Vehicle Care
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 switchto 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 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.