2020 CHEVROLET LOW CAB FORWARD power steering

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
Vehicle Care 255
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)
Caution (Continued)
hosing. Eventual leakage of HBB
oil, sudden increase in brake
pedal resistance and fire could
unexpectedly result in a crash.
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

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
306 Vehicle Care
Front End Towing (All Wheels On
the Ground)
Your vehicle may be towed on all
wheels provided the steering is
operable. Remember that power
steering and brakes will not have
power assist. There must be a tow
bar installed between the tow
vehicle and the disabled vehicle.
Towing with all wheels on theground
1. Bumper
2. Tow Hook
3. Front Axle
4. Towing Guide
5. Towing Chain
To prepare a disabled vehicle for
front end towing with all wheels on
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.
Provide wood blocking to prevent
towing chains and bar from coming
into contact with the bumper.
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. 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. Check and fill rear axle with
oil, if required.
Rear End Towing
When towing a vehicle with rear
wheels raised, secure the steering
wheel to maintain straight-ahead
position. Make certain that the front
axle is not loaded beyond the front
axle gross axle weight rating
(GAWR) as indicated on the
vehicle's VIN and weight rating
plate.
Special Towing Instructions
1. All state and local laws regarding such items as
warning signals, night
illumination, speed, etc., must
be followed.
2. Safety chains must be used.

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 323
No. Service Interval16 000 km/10,000 mi
24 000 km/15,000 mi
32 000 km/20,000 mi
48 000 km/30,000 mi
64 000 km/40,000 mi
72 000 km/45,000 mi
80 000 km/50,000 mi
96 000 km/60,000 mi
112 000 km/70,000 mi
120 000 km/75,000 mi
128 000 km/80,000 mi
144 000 km/90,000 mi
160 000 km/100,000 mi
168 000 km/105,000 mi
176 000 km/110,000 mi
Service intervals
months or
kilometers
(miles)
whichever
occurs first (1)
26 Differential gear oil I - I R I - I R I - I R I - I or every
24 months
27 Power steering fluid - - - R - - - R - - - R - - - or every
24 months
28 Power steering oil hoses - - - - - - R - - - - - R - - or every
24 months
29 Steering wheel free
play (4) Every 10 400 km (6,500 miles): I
30 Steering gear box torque - - T - T - - T - - T - T - - or every
12 months
31 Drive shaft flange torque T - T T T - T T T - T T T - T or every
12 months
32 Drive shaft lubrication L - L L L - L L L - L L L - L or every
12 months
33 Leaf spring U-bolt
torque (4) T - T T T - T T T - T T T - T

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
328 Service and Maintenance
21. Brake Fluid :Check the fluid in
the brake fluid reservoir every
16 000 km (10,000 miles). Replace
the fluid every 48 000 km
(30,000 miles).
22. Hydraulic Brake Booster Fluid
(5500HD, 5500XD models) :
Replace Dexron VI ATF fluid every
24 months or 30,000 miles
(48,000 km), whichever occurs first.
23. Brake Line and Hoses : Check
lines and hoses for proper hook-up,
binding, leaks, cracks, chafing, etc.
every 32 000 km (20,000 miles).
Any questionable parts should be
replaced or repaired at once. When
rubbing or wear is noted on lines or
hoses, the cause must be corrected
at once.
24. Parking Brake Cable : Check
the parking brake cable every
16 000 km (10,000 miles) or
12 months whichever occurs first.
25. Automatic Transmission
Fluid : Check the automatic
transmission fluid level at each engine oil change and replace fluid
every 48 000 km (30,000 miles). Do
not overfill.
26. Differential Gear Oil :
Replace
lubricant every 48 000 km
(30,000 miles). Check lubricant level
every 16,000 km (10,000 miles) or
every 12 months, and add lubricant
to within 0 to 10 mm (0 to 0.4 inch)
of the bottom edge of the filler hole
if necessary.
27. Power Steering Fluid :
Replace power steering fluid every
24 months or 48 000 km
(30,000 miles), whichever occurs
first.
28. Power Steering Oil Hoses :
Replace power steering oil hoses
every 24 months or 80 000 km
(50,000 miles), whichever occurs
first.
29. Steering Wheel Free Play :
Check steering wheel free play after
the first 1 040 km (650 miles) and
then every 10 400 km (6,500 miles).
Steering wheel free play
10-50 mm (0.39-1.97 in) 30. Steering Gear Box Torque :
Retighten the attaching bolts of the
steering gear box to the specified
torque every 12 months or every
32 000 km (20,000 miles) whichever
occurs first.
Steering gear box tightening torque
103 Y(76 lb·ft)
31. Driveshaft Flange Torque :
Check the fixing bolts of driveshaft
flange for looseness or damage
after the first 16 000 km
(10,000 miles). Driveshaft flange tightening torque
103Y(76 lb·ft)
32. Driveshaft Lubrication :
Lubricate the grease fitting on the
center bearing, as well as each
universal joint and spline coupling
every 12 months or 16 000 km
(10,000 miles) whichever occurs
first.

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
330 Service and Maintenance
Owner Checks and
Services
Before Driving
Proper care and driving is important
not only for extended service life of
your vehicle, but also for improved
fuel and oil economy. Drive carefully
and defensively. Be sure you know
how to use your truck and its
equipment before operating it.
Starting and Operating
Proper care and operation will not
only extend the service life of your
vehicle but also improve fuel
economy.
Check Around the Vehicle Before
Starting the Engine
Before pulling away, perform a
thorough safety check, making sure
there are no children or obstructions
around the vehicle.
Take off the chocks after confirming
that the parking brake is securely
applied. Sit behind the wheel, adjust
the seat position, and buckle up theseat belt. The passengers are also
required to buckle up the seat belts.
Adjust the positions of the steering
wheel and mirrors. Lock the doors.
Turn the power of the dome light or
accessories OFF before starting the
engine.
Engine Conditions
Checking the Engine for
Startability and Abnormal Noises
1. Make sure the parking brake is securely engaged. Step firmly
on the brake pedal.
2. Make sure the selector lever is in "P" or "N" position.
For safety, firmly press the
brake pedal before starting the
engine.
3. Turn the engine control switch to start the engine.
Check that the engine starts
quickly with no abnormal
noises. Checking Condition of the Engine
at Low Speeds and during
Acceleration
1. Make sure the transmission is in the "P" or "N" position and
the parking brake is securely
engaged.
2. Turn the engine control switch to start the engine, and run it to
warm up.
3. Check that the engine is running at a speed within the
standard idle speed range.
During regeneration of the
diesel particulate filter (DPF),
the engine idle speed may
increase.
4. Drive the vehicle, making sure the accelerator pedal does not
stick when gradually
accelerating, the engine speed
rises smoothly and it does not
knock.

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 331
Recommended Daily
(Pre-operation) Inspections
These checks are in addition to, not
instead of, any legally required daily
inspections. See related topics
under "Maintenance Schedule",
especially if problems are found.
For safe and comfortable driving,
keep record of the distances driven
and the condition of the vehicle
during operation. Perform
inspections at appropriate intervals,
and perform maintenance in
accordance with the findings of the
inspections. If an inspection reveals
an abnormality or there was an
abnormality the previous time the
vehicle was driven, have the vehicle
repaired by the nearest dealer
before it is driven again.1. Components that showed abnormalities during the
previous operation
.Check components that
showed abnormalities
during the previous
operation 2. Checks performed at the
engine
.Fan belt looseness and
damage
. Engine oil level
. Engine coolant level
. Power steering fluid level
3. Checks performed from the driver's seat
.Brake fluid level
. Brake pedal free play
. Operation of meters,
gauges and warning/
indicator lights
. Engine startability,
abnormal noise and color of
exhaust gases
. Parking brake lever stroke
. Windshield washer fluid
spray condition and
windshield wiper
effectiveness
. Windshield washer fluid
level .
Steering wheel position and
free play
. Operation of horn and turn
signal lights
. Door lock operation
4. Checks performed during a walk around the vehicle
.Illumination, flashing,
contamination, damage and
obstruction of lights
. Contamination, damage ad
obstruction of windows,
mirrors and reflectors
. Leaf spring damage
. Oil, engine coolant, fuel,
brake fluid and power
steering fluid leaks
. Water separator
5. Checking wheels and tires .Air pressure
. Cracks and other damage
. Abnormal wear
. Tread depth

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
332 Service and Maintenance
.Mounting condition of all
wheel nuts
6. Checks performed after the engine startup
.Oil, engine coolant, fuel,
brake fluid and power
steering fluid leaks
. Inspect the exhaust system,
checking that the tailpipe is
clear
7. Checks performed while driving the vehicle
.Brake effectiveness
. Engine abnormal noises
Keep the Floor Around the Driver
Seat Clean and Tidy
{Warning
It is extremely dangerous to have
empty cans, empty bottles,
or other items rolling around on
the floor because they could get
trapped under the brake pedal
and prevent brake application. (Continued)
Warning (Continued)
For proper pedal operation, it is
also essential to lay floor mats
properly. Incorrectly installed floor
mats would hinder free movement
of the pedals.
Do not use the dashboard pocket
or the top of the dashboard as a
place to put items that could roll,
which could interfere with your
driving. You and others could be
seriously injured.
Choose Your Footwear Suitable
for Driving
{Warning
Choose footwear that ensures
proper operation of pedals when
driving the vehicle. Use of
footwear unsuitable for driving
may cause an accident. The
driver could be seriously injured
when not wearing the proper
footwear.
Electrical System
Following the after-delivery service,
it is the owner's responsibility to
check all wiring periodically for
cracked, chafed or oil-soaked
insulation and maintain it in a clean
and tight condition to ensure
satisfactory operation of the
electrical system.
Headlights and Turn Signal
Lights
Turn the engine control switch to the
"ON" position, and then check the
way in which the headlights, turn
signal lights, and other exterior
lights come on and flash. In
addition, press the brake pedal to
confirm whether the stop lights
come on, and shift the transmission
to "R" position to confirm whether
the back up lights come on. Also
examine the lights for discoloration,
damage, and looseness.