2020 CHEVROLET LOW CAB FORWARD transmission

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
Driving and Operating 139
{Warning
To reduce the risk of personal
injury, before going down a steep
or long grade, reduce speed, turn
on the exhaust brake and shift the
transmission to the next lower
gear. This will help control your
speed. Do not hold the brake
pedal down too long or too often
while going down a steep or long
grade. This could cause the
brakes to get hot and not to work
as well. As a result, the truck will
not slow down at the usual rate.
Failure to take these steps could
result in loss of vehicle control.
You and others could be seriously
injured.
Brake Effectiveness When the
Vehicle Has Been Driven on a
Flooded Road or Washed
{Warning
When the vehicle is driven on a
flooded road, parked on a flooded
road or washed, water can get
into the brakes and reduce their
effectiveness. If the brakes do not
work well afterward, drive slowly
and gently press the brake pedal
several times until the brakes dry
out and start working normally.
Always do this after driving
through water or washing the
vehicle to help reduce the risk of
personal injury. Before parking
the vehicle in winter, press the
brake pedal several times in the
same way to get rid of moisture in
the brakes. Otherwise, the
moisture in the brakes may freeze
and make the vehicle immovable.
You and others could be seriously
injured.If the vehicle must be driven on a
flooded road or is parked in an area
that becomes flooded, promptly
perform a check for the following
points:
.
Effectiveness of the brakes
. Water-ingress or damage to
drum brakes, disc brakes
. Engine damage due to
water-ingress
. Shorting of electrical
components
. Oil level and degradation
(cloudiness) of the engine,
transmission, differential
. Greasing of each components
(lubrication)

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
144 Driving and Operating
{Warning
If you park in a place where there
is a lot of snowfall, snow
accumulating around the vehicle
could limit ventilation. Running
the engine with the vehicle in
these conditions could cause
exhaust gases to enter the cabin,
resulting in carbon monoxide
poisoning. Take preventive action
by, for example, clearing the snow
around the vehicle.
You and others could be seriously
injured.
Do not park under trees or under
the eaves of a building. Chunks of
ice could fall on the vehicle if you
park in such a place.
Cleaning the Vehicle after
Driving on Snowy Roads
. The vehicle speed sensors are
fitted on the wheels. When
removing snow, ice, and other
incrustation, take great care not
to damage the components. .
Do not use a sharp implement to
remove snow. Sharp edges
could damage rubber parts.
Refer to Antilock Brake System
(ABS) 0207.
Remove snow that has stuck to the
inside of the fenders and to the
brake hoses. Otherwise, it may
damage components. After driving
on a salted road, wash the
underside of the vehicle as soon as
possible to prevent the salt from
causing rust. Spraying water under
high pressure is an effective way to
get the salt off.
After washing the vehicle, wipe the
door openings dry.
If the Vehicle Is Stuck
When Driving on Bad Roads
Caution
Do not spin wheels faster than
32 km/h (20 mph) in mud, sand,
snow, ice, or other poor road (Continued)
Caution (Continued)
conditions. Damage may result
from excessive wheel spinning,
including tire, transmission, and/
or rear axle malfunction.
If the vehicle gets stuck and it is
difficult to get out, immediately
stop driving and have the vehicle
towed.
If the vehicle gets stuck in sand,
mud, snow or ice, move the selector
lever from 2 to the R position. Apply
a light pressure to the accelerator
pedal while the transmission is in
gear. Remove your foot from the
accelerator and press the brake
pedal while shifting. Do not race the
engine. For best traction, avoid
spinning the wheels. When you
cannot avoid driving through deep
mud, using tire chains is an effective
way to avoid getting stuck.
When driving in sand or mud, avoid
hard braking, sudden acceleration,
and sharp turns of the 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
154 Driving and Operating
SymptomCauseCorrective Action Reference
Loud or abnormal
noises From the
transmission
Insufficient
transmission oil
Add oilSee
Automatic
Transmission Fluid
0 241
Transmission inner
components faulty
4-
From differential Insufficient differential
gear oil
Add oilSee
Rear Axle
(Gear Oil Viscosity
Chart) 0261 or
Rear Axle (Oil
Level Check) 0262
Differential inner
components faulty
4-
From the
suspension Spring pins, shackles,
or stoppers worn
4-
From the driveshaft Poor lubrication in each
component
Lubricate themSee
Owner Checks
and Services 0330
Splines or bearings worn
4-

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
156 Driving and Operating
If There is a Fuel Leak
{Danger
Leaking fuel from the vehicle is
dangerous due to possible
combustion or explosion. Stop the
engine immediately.
You and others could be seriously
injured or killed.
Starting and
Operating
New Vehicle Break-In
Good vehicle care begins with
proper break-in. While every new
vehicle goes through rigid factory
and dealer inspection and tests
before delivery, the care you give
your vehicle during the initial
break-in period can pay off in longer
life, better performance and more
economical operation.
It is therefore always recommended
that during the initial 1 000 km
(600 mile) break-in period, the
following few simple precautions are
carefully observed.
Follow the recommendations listed
below:
.Warm up the engine by driving
easily for the first few minutes
before placing it under load.
. Do not drive for extended
periods at any one constant
speed, either fast or slow, during
the first 800 km (500 miles). .
Use the correct gear to maintain
the desired road speed without
lugging the engine.
. Avoid racing the engine,
full-throttle starts and aggressive
application of brakes when
stopping.
. Keep tires properly inflated for
the load carried.
. Check lubricant levels in the
engine and transmission weekly.
. Keep speeds below 80 km/h
(50 MPH) for the first 800 km
(500 miles).
. Use the lowest gear ratio
available when starting a loaded
vehicle and when climbing
slopes to avoid lugging the
engine.
. It is recommended that the
engine speed is restricted to
2,300 r/min.

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
162 Driving and Operating
filled before leaving the vehicle
standing for an extended
period.
Do not use starting aids in the air
intake system. Such aids can cause
immediate engine damage. See
Fuel for Diesel Engines 0218.
Stopping the Engine
When stopping the engine, take the
following steps: 1. Bring the vehicle to a complete stop.
2. Firmly apply the parking brake.
3. Move the selector lever to the P position and make sure that
the shift indicator shows P.
4. Allow the engine to idle for approximately 3 minutes.
5. Turn the engine control switch to the ACC or LOCK position.
Do not shut down the engine
immediately after driving the vehicle.
Otherwise, a seizure or other
failures may result. To prevent the battery from going
dead, turn the engine control switch
to the ACC or LOCK position after
stopping the engine. If you leave the
vehicle for an extended period of
time, place the engine control switch
in the LOCK position.
Let the engine idle for 3 minutes
before shutting off the engine. This
allows the turbocharger to slow
down while keeping the bearings
lubricated.
If the Vehicle Has Not Been Used
for a Long Period
If a diesel vehicle has been
standing for an extended period of
time, the turbocharger bearings
should be pre-lubricated prior to
starting. See your authorized dealer
for more detailed information.
Before using a vehicle that has not
been driven for a long period, check
the engine and transmission for oil
leakage, and make sure the oil is at
the required levels. If there is
insufficient oil, it will not adequately
reach and lubricate components,
and a breakdown will result.Start the engine and allow it to idle
for at least five minutes. Check for
abnormal noises.
For instructions on warming up the
engine, refer to
“Starting the Engine”
previously in this section.
If one year has passed since the
diesel exhaust fluid (DEF) in the
DEF tank was added, the DEF in
the tank should be replaced. Be
careful not to inhale the ammonia
odor when replacing the DEF. Also,
please contact your nearest dealer
about the replacement work.
Operating Temperature
Recommendations for Warming
Up the Engine
The engine is sufficiently warmed
up when the needle of the engine
coolant temperature gauge starts
to move.
Do not race the engine or quickly
accelerate before the engine has
sufficiently warmed up. Oil would
not have adequately reached and
lubricated components, and a
breakdown may result.

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
Driving and Operating 165
If the idling stop function does not
initiate, a transmission related
problem may have occurred. Please
contact your dealer. (There is a
Diagnostic Trouble Code (DTC) that
inhibits the idling stop function when
the Service Transmission Warning
Light is not illuminated).
High Idle System
Use high idle mode to increase
engine idle speed to 1,200 r/min
when the vehicle is stationary.
Activating High Idle Mode
Follow the below procedure to
activate the high idle mode:1. Set the parking brake.
2. Set the selector lever in P (Park) or N (Neutral) position.
3. Do not press the brake pedal. 4. Press the cruise control main
switch to set it to ON. At this
time, the operation indicating
light will turn to green.
5. Turn and hold the cruise control set switch in the SET
position. After approximately
3 seconds the cruise control
set indicator light will begin to
flash slowly and the engine idle
will increase to 1,200 r/min.
Canceling High Idle Mode
Any of the following actions will
cancel high idle mode.
. The cruise control main switch is
set to OFF.
. The brake pedal is pressed.
. The parking brake is released.
. The selector lever is moved from
P (Park) or N (Neutral) position.
. The accelerator pedal is
pressed, accelerating the engine
beyond the engine speed
threshold.

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
196 Driving and Operating
When the exhaust system warning
light comes on, promptly have the
vehicle inspected and serviced at a
dealer.
When a malfunction is detected in
the SCR system, the warning and
the indicator lights shown in the
table come on. SeeVehicle
Messages 074, Malfunction
Indicator Lamp (Check Engine
Light) 061, and Diesel Exhaust
Fluid (DEF) Warning Light 068.
When the Diesel Exhaust Fluid
(DEF) Tank is Empty
If the DEF tank is empty and
warning and indicator lights are on,
you must follow below procedure to
cancel the vehicle restriction: 1. Turn the engine control switch to the LOCK or ACC position,
and add DEF.
2. After adding DEF, turn the engine control switch to ON
position.
3. Wait until buzzer stops, warnings and indicators are
turned off. 4. If the buzzer does not stop,
return the engine control switch
back to the LOCK position and
add more DEF, and then start
over from step 2 above.
5. Restart the engine.
It may take a while until the warning
lights and indicators turn off and the
buzzer stops after turning the
engine control switch to the ON
position.
It is desirable to fill up the tank with
DEF to avoid DEF remaining level
warning indication from reappearing.
When the outside temperature is
low, refer to Adding DEF in Cold
Weather. See Driver Information
Center (DIC) 070, Brake System
Warning Light (Parking Brake Light)
0 62, Warning Buzzers 079, and
Winter Driving 0142.Automatic
Transmission
On an automatic transmission
vehicle, the driver does not use a
clutch pedal when pulling away,
changing gears, or stopping. Only
the selector lever, accelerator pedal,
and brake pedal are used.
Practice learning the characteristics
of the automatic transmission
vehicle and how to correctly operate
it. When the vehicle is stationary,
remember to keep the brake pedal
firmly pressed, and if necessary,
move the selector lever in the P or
N position and apply the parking
brake.
Creep : With the engine running
and a gear position other than P or
N selected with the selector lever,
power reaches the wheels even
when the accelerator pedal is not
pressed, causing the vehicle to tend
to move.

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
Driving and Operating 197
Furthermore, the higher the engine
speed, the stronger the creep and
the greater the vehicle's tendency
to move.
Starting
Start the engine in either the P or
the N position. The engine should
not start in any other selector
position. If it does, something is
wrong. Have your truck checked by
your dealer as soon as possible.
Always apply either the foot brake
or the parking brake before shifting
into any driving position. This will
prevent creeping.
The engine should be running at
idle when shifting from P or N to one
of the driving positions. See
Selector Lever0205.
Caution
Do not apply water from a
high-pressure washer nozzle
directly to the electric connectors.
(Continued)
Caution (Continued)
Failure to observe this precaution
can lead to faulty operation of the
electrical system.
Caution
Never move the selector into the
P position when the vehicle is in
motion. This will damage the
automatic transmission.
Firmly press the brake pedal to
prevent the vehicle from moving
even if it is stopped on a level road,
and move the selector lever into P
and firmly apply the parking brake
as needed.
The engine speed rises and
creeping will be stronger than usual
during the conditions noted below.
Keep the brake pedal firmly
pressed:
. Immediately after engine
start up. .
While the air conditioner is
running.
. During the diesel particulate filter
(DPF) regeneration.
How to Use the Automatic
Transmission
{Warning
Before starting the engine, move
the selector lever into P or N (P is
preferred), make sure the shift
indicator indicates P or N, pull up
the parking brake lever and firmly
press the brake pedal.
When moving the selector lever to
any position other than P, be sure
to press the brake pedal.
Never leave the driver's seat with
the selector lever placed in D, 2,
1 or R. The vehicle may start
moving. When leaving the driver's
seat, be sure to move the selector
lever into P and securely set the
parking brake. (Continued)