2020 CHEVROLET LOW CAB FORWARD maintenance

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.

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
256 Vehicle Care
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 crashes.
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
low, add fluid up to the "MAX" line.
Be sure to use Dexron VI ATF fluid
when adding fluid. The brake
booster reservoir is located behind
the cab on the left side.
Brake Pedal
Stroke
Shut off the engine and press the
brake pedal about 10 times strongly,
then check the brake pedal for free
play by lightly pushing it by hand
until you feel resistance.

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
258 Vehicle Care
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
Remove the inspection cover (1) on
the left- hand side of the instrument
panel by turning it with your fingers.
Check that the fluid level in the
reservoir is between the "MAX" and
"ADD" lines.
If the fluid surface cannot easily be
seen, rock the vehicle gently.
Adding Brake Fluid
If the level of brake fluid has
dropped below the "ADD" line,
remove the cap (2) and add fluid.
Take care to avoid filling beyond the
"MAX" line.
Tighten the cap securely after the
fluid has been added.
When adding brake fluid to the tank,
take care to prevent dirt and water
from entering it. Any dirt or water in
the system could cause the vehicle
to lose braking functions.
Inspect and change brake fluid
according to the Maintenance
Schedule.
Use the recommended brake fluid
when adding brake fluid.