service 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
Vehicle Care 281
No. Description Rating17 IGNITION 2 10A
18 IGNITION 1 10A
19 TRANSMISSION 5A
20 ECM 10A
21 METER 10A
22 ECU (BATT) 10A
23 MIRROR 10A
24 AUDIO, ACC 15A
25 HORN 15A
26 TURN, HAZARD 15A
27 TAIL LAMPS 10A
28 ILLUMINATIONS 10A
29 CORNERING LAMPS 10A
30 AIR CONDITIONER 10A
31 – –
32 – –
33 – –
34 – – No. Description Rating
B-1 BACK UP LIGHT 10A
B-2 BACK UP LIGHT (SERVICE) 10A
B-3 AUDIO REVERSE MUTE 10A
B-4 PTO 10A
D-1 CIGAR 20A
D-2 ACCESSORIES SOCKET 15A
D-3 POWER SOURCE 20A
D-4 SPARE 5A

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 285
{Warning
Always use fuses specified by the
dealer when replacing the
slow-blow fuse. Using fuses with
a rating other than that specified,
or using wire or tin foil, etc., could
result in fire or damage.
If the new fuses blow right away
and the cause is unknown,
contact your dealer.
Do not inspect or replace fuses
when the starter switch is in the
ON position. Doing so may lead
to an accident.(Continued)
Warning (Continued)
When inspecting fuses, be sure to
park the vehicle on flat, level
ground and apply chocks to the
wheels.
It is not necessary to open or close
the cover unless trouble is found.
The relay box structure makes it
difficult for water to enter. If you
should spill water or a beverage of
the cover, however, wipe it off
before opening the cover.
The area around the cover will get
warm when the vehicle is being
driven, but this is not abnormal.
Wheels and Tires
The operating load and cold inflation
pressure on the rim and wheel must
not exceed the rim and wheel
manufacturer's recommendations
even though the tire may be
approved for a higher load or
inflation. Rim and wheel may be
identified (stamped) with maximum
load and maximum cold inflation
rating. For rims and wheels not so
identified or for service conditions
exceeding the rate capacities,
consult the rim and wheel
manufacturer to determine rim and
wheel capacities for the intended
service. The factory-installed tires
on this vehicle were selected to
provide the best all-around tire
performance for normal operation.
When inflated, as shown on the
vehicle, they have the load carrying
capacity to operate satisfactorily at
all loads up to and including the full
rated load specified for the vehicle.
For more information concerning the
differences in capacities of tires and

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
294 Vehicle Care
Damaged Tires
{Danger
It is dangerous to mount the
wrong size tire on a wheel. If you
do so, the tire/wheel can explode
as air is being added. This
explosion may result in severe
personal injury or death. To learn
which wheels and tires are
correct, look at the "VIN, Weight
Rating, and Greenhouse Gas
(GHG) Emissions Plate" on the
left side rear pillar panel below
the striker (single cab) or on the
left center pillar panel beside the
shoulder seat belt anchor (crew
cab). Wheel size is also stamped
on the side of each wheel.
To help avoid personal injury and
property damage if a wheel must
be changed, seek expert tire
services if you can. If you must
remove the wheel without any
such help, do the following:(Continued)
Danger (Continued)
.If the tire looks as if it may
be underinflated, stand to
the side and check whether
the wheel assembly
appears normal by
comparing it to another
wheel assembly on the
vehicle.
. Let the air out of the tire by
taking out the valve core.
If you have a way to put air
back in a tire, note that it is
good safety practice to let
the air out of both tires of a
dual assembly before taking
off the damaged tire and rim
assembly from the vehicle.
After letting out the air, take
off the tire and rim assembly
and install a spare tire and
rim assembly.
If your vehicle is equipped
with a differential lock
system or limited slip
differential (LSD), it might
(Continued)
Danger (Continued)
start moving when the
engine power is transmitted
to the rear axle even when
one of the wheels on the
axle is raised clear of the
ground. Do not start the
engine with any rear wheel
in contact with the ground.
If you are not fully
experienced on the
procedures to follow, and/or
are not equipped with the
proper tools and equipment,
again, do not attempt to
raise the vehicle, or remove
or install the tire and wheel
assembly—seek expert tire
services.
. Do not put air back in a tire
that has been run flat, or is
seriously low on air, without
first having the tire taken off
the wheel and the tire
checked for damage.
(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
Vehicle Care 295
Danger (Continued)
.Note that taking off and
mounting tires on wheels
requires proper tools, safety
equipment and special
training. A person can be
severely injured or killed
and damage can result from
using the wrong service
methods. Truck tires and
wheels should be serviced
only by trained people using
the proper equipment.
. Never add air to your tires
unless an accurate pressure
gauge is also used. When
putting air in a tire on the
vehicle, stand to the side
and use a clip-on chuck and
hose extension. In choosing
the right tire pressure, be
careful not to exceed the
maximum pressure
capability shown on the tire;
see the tire pressure charts
in this manual.
(Continued)
Danger (Continued)
.Tire mounting or repair can
result in serious personal
injury or death, if not
performed correctly. This
section has detailed
instructions for proper wheel
and tire replacement, so be
sure to read and follow
them. Truck fleet owners
and operators: You can get
written instructions on truck
tire demounting, repair and
mounting from Rubber
Manufacturers Association
(RMA), 1400 K Street N.W.,
Washington, D.C. 20005,
and also from many tire
stores. Wheel Nut Torque{Warning
Never use oil or grease on studs
or nuts. Use the torque specified
for the type of wheels on the
vehicle. Snug all wheel nuts and
then tighten to the specified
torque in the numerical sequence
shown. Improperly tightened
wheel nuts could eventually allow
the wheel to come off while the
vehicle is moving, possibly
causing loss of control and
personal injury and property
damage.
When the vehicle, wheel or
fasteners are new, have a
technician tighten wheel stud nuts
and rim clamp nuts with a torque
wrench at 1 040 km (650 mi). This is
necessary because the clamping
system used on the wheels must
seat before the fastener will hold a
uniform clamp load and remain fully
tightened. Also have a technician

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 297
Tire Pressure
Tire Load and Inflation Table
Tire Load and Inflation Table
TIRES FOR VEHICLES IN HIGHWAY SERVICE
TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES
Tire Size Designation Cold Inflation Pressure (psi) 50 55 60 65 70 75 80 85 90 95
LT215/85R16E Dual Single(lbs) 2470
2680
225/70R19.5F Dual Single(lbs) 3115
33153245
34503415
3640
See Wheels and Tires 0285.
Tire Rotation
{Warning
Be sure to check the wheel studs,
wheel nuts and disc wheel for any
abnormality whenever the disc
wheel is removed.
(Continued)
Warning (Continued)
If you find any abnormal condition
on the wheel studs, wheel nuts or
disc wheel, do not continue to use
the wheel. Contact the nearest
dealer as soon as possible
Tires at different locations wear
differently. For uniform tire wear and
longer tire life, you should rotate the
tires on your vehicle regularly. Make sure to use tires of the same type
on the same axle. If you install tires
of different types on the same axle,
the vehicle may drift right or left
when you apply the brakes.
New tires are more likely to build up
heat and wear faster than old tires,
so they should be installed on the
front axle where the load is smaller.
If there is a difference in diameter
between the inner and outer tires of
a dual-tire wheel, install the smaller
diameter tire inside.

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
300 Vehicle Care
3. Next, tighten the outer wheelnuts to the specified torque.
{Warning
If you find any abnormal
conditions with the wheel nuts
such as frequent loosening of
retightened nuts, have your
vehicle checked or serviced at the
nearest dealer as soon as
possible.
Fully engage the wheel wrench on a
wheel nut in order to tighten the nut
to the specified torque. However, do
not use a pipe as a handle
extension or your foot to apply force
on the wrench. This would tighten
the nut more than required and
might damage components.
Both under-tightening and
over-tightening of wheel nuts may
cause broken wheel studs or
cracked disc wheels and could lead
to wheel detachment. Adhere to the
specified tightening torques. When replacing a tire with a new
one, use only a tire of the same
type and size as the replaced tire;
otherwise, driving safety could be
affected. Avoid mixed use of
different types or different size tires
at all costs.
If a Tire Goes Flat
When the tire goes flat while driving,
ease off the accelerator pedal, avoid
hard braking, hold on to the steering
wheel firmly, and stop the vehicle.
The tire should be changed in a
safe, open location to prevent
obstructing other vehicles or
pedestrians.
{Warning
If you continue to drive on a flat
tire, undue force will be applied to
the wheel studs, possibly causing
the studs to break and the wheel
to come off. You and others could
be seriously injured.
See “Tire Replacement
Recommendations” underWheels
and Tires 0285.

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 305
Towing the Vehicle
Consult your dealer or a
professional towing service if the
disabled vehicle must be towed.
Proper equipment must be used to
prevent damage to vehicles during
any towing. State and local laws
which apply to vehicles in tow must
be followed. Vehicles should not be
towed at speeds in excess of
88 km/h (55 mph).
Connect to the main structural parts
of the vehicle. Do not attach to
bumpers, tow hooks or brackets.
Use only equipment designed for
this purpose. Follow the instructions
of the wrecker manufacturer.
A safety chain system must
be used.
The procedures below must be
followed when towing to prevent
possible damage.Front End Towing (Front Wheels
Off Ground)
To prepare a disabled vehicle for
front end towing with front wheels
raised off the ground, the following
steps are necessary:
.
Block the rear wheels of the
disabled vehicle.
. Disconnect the driveshaft at the
rear axle. Secure the driveshaft
to the frame or crossmember.
When towing, disconnect the
driveshaft at the rear axle to ensure
the transmission is not damaged.
The rear end of the driveshaft must
be disconnected and safely secured
if the 80 km (50 mi) or 48 km/h
(30 mph) is exceeded.
If there is damage or suspected
damage to the rear axle, remove the
axle shafts. Cover the hub openings
to prevent the loss of lubricant or
entry of dirt or foreign objects.
Place a 10 cm (4 in) wood beam
against the towing guide behind the
bumper. (If no 10 cm (4 in) is
available, then remove the bumper.) Ensure towing chains do not come
into contact with the horns or the
bumper. (If towing chains contact
the bumper, then remove the
bumper.)
1. Horns
2. Bumper
After Towing
After towing the vehicle, block the
rear wheels and install axle shafts
or driveshaft.
Apply the parking brake before
disconnecting from the towing
vehicle.

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
312 Vehicle Care
When cleaning the radiator core (1)
and charge air cooler core (2) , do
not crush or damage the fins (3).
The fins are very fragile so be
careful not to bend them out of
shape. If they become deformed,
their cooling efficiency will be
impaired. Before cleaning, take
steps to ensure that no water will
splash onto the surrounding
electrical components and wires.
If stubborn dirt still remains even
after the radiator core and charge
air cooler core (diesel) have been
cleaned, have the vehicle inspected
and serviced.
Corrosion Protection
Your vehicle has been designed and
built to resist corrosion. Special
materials and protective finishes
were used on most parts of your
vehicle when it was built to help
maintain good appearance,
strength, and reliable operation.
However, some parts which
normally are not visible (such as
those under the vehicle and under
the hood) are such that surface rust
will not affect their reliability. So
corrosion protection is not needed
or used on these parts.
Sheet Metal Damage
If your vehicle is damaged and
requires sheet metal repair or
replacement, make sure the body
repair shop applies anti-corrosion
material to the parts repaired or
replaced so that corrosion protection
is restored. (Also see "Finish
Damage" which follows.)Foreign Material Deposits
Calcium chloride and other salts,
ice-melting agents, road oil and tar,
tree sap, bird droppings, chemicals
from industrial chimneys and other
foreign matter may damage vehicle
finishes if left on painted surfaces.
Prompt washing may not completely
remove all of these deposits. Other
cleaners may be needed. When
using chemical cleaners, be sure
they are safe for use on painted
surfaces.
Finish Damage
Any stone chips, fractures or deep
scratches in the finish should be
repaired promptly. Bare metal will
corrode quickly and may develop
into major repair expense. Minor
chips and scratches can be repaired
with touch up materials available
from your authorized dealer or other
service outlets. Larger areas of
finish damage can be corrected in
your dealer's body and paint shop.

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
Service and Maintenance 317
Service and
Maintenance
Maintenance Schedule
Maintenance Schedule . . . . . . . 317
Owner Checks and Services
Owner Checks andServices . . . . . . . . . . . . . . . . . . . . 330
Additional Maintenance
and Care
Additional Maintenanceand Care . . . . . . . . . . . . . . . . . . . . 336
Recommended Fluids,
Lubricants, and Parts
Recommended Fluids andLubricants . . . . . . . . . . . . . . . . . . . 339
Maintenance Replacement Parts . . . . . . . . . . . . . . . . . . . . . . . . 341
Maintenance
Schedule
Caution
Damage caused by improper
maintenance can lead to costly
repairs and may not be covered
by the vehicle warranty.
Maintenance intervals, checks,
inspections, recommended fluids,
and lubricants are important to
keep the vehicle in good working
condition.
Do not have chemical flushes that
are not approved by GM
performed on the vehicle. The
use of flushes, solvents, cleaners,
or lubricants that are not
approved by GM could damage
the vehicle, requiring expensive
repairs that are not covered by
the vehicle warranty.
Make sure the vehicle is inspected
at regular intervals. Inspections and
maintenance enable you to use the vehicle with peace of mind. They
also extend the vehicle's
service life.
For safe and economical driving, we
recommend that you have your
vehicle inspected and serviced
regularly according to the schedule
indicated in this chapter.
To drive your vehicle safely and at
minimum cost, it is essential to have
your vehicle regularly inspected and
serviced at your dealer as per the
specified maintenance schedule.
Contact your dealer for inspection
that requires disassembly and/or
special equipment.
The Maintenance Schedule in this
manual and a Warranty Information
Booklet are supplied with your
vehicle. Read all publications for a
full understanding of your vehicle's
maintenance needs.
The quality of maintenance your
new vehicle receives is as important
as the regularity with which it is
serviced. Authorized dealers provide
nationwide quality in customer
service. The program includes 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
318 Service and Maintenance
training of dealer technicians
throughout the country and is
supported with a continuous
follow-up of publications and other
service information. The use of
genuine parts and accessories,
which have the same high quality
standards as original equipment
parts, and the use of factory
approved tools developed and
tested for use by the authorized
dealer also contribute to the high
quality of service.
If you have any questions on how to
keep your truck or chassis in good
condition, see your authorized
dealer, the place many truck owners
choose to have their maintenance
work done. Your authorized dealer
can be relied upon to use proper
parts and practices.
Some of these services can be
complex, so unless you are
technically qualified and have the
necessary equipment, you should
let your authorized dealer's service
department or another qualified
service center do these jobs.The schedule includes general
maintenance which you or a
qualified technician should perform
periodically.
Explanation of Vehicle
Maintenance and Log
The following is a brief explanation
of normal vehicle use.
NORMAL VEHICLE USE—The
maintenance instructions contained
in this section are based on the
assumption that your vehicle will be
used as designed:
.
To carry passengers and cargo
with the limitations indicated on
the vehicle VIN and GVW plate.
. On reasonable road surfaces
within legal operating limits.
. On a daily basis, as a general
rule, for at least several miles/
kilometers.
Unusual operating conditions, such
as driving in dusty areas (sweeper,
agricultural or off-road vehicles),
extended idling (refrigeration vehicles), or vehicles operated for
frequent short trips, will require
more frequent vehicle maintenance.
The log groups items according to
mile/kilometer service intervals. Use
the item codes (letter and number)
to find the description of the
maintenance and the time intervals.
Follow whichever interval comes
first, time or miles/kilometers.
After the maintenance services are
performed, insert the month, day
and mileage/ kilometers in the area
provided next to the serviced item.
The services shown up to
176 000 km (110,000 miles) are to
be repeated after the initial
176 000 km (110,000 miles) at the
same intervals.
Severe Driving Conditions
A vehicle operated under severe
conditions (see list below) requires
more frequent maintenance.
.
Frequent short trips of less than
6 kilometers (4 miles) in
moderate temperatures