2021 CHEVROLET SILVERADO 2500HD automatic transmission

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Introduction 5
1. Tow/Haul Mode (On Some Models). SeeDriver Mode Control 0244.
Automatic Transfer Case Control (If
Equipped). See Four-Wheel Drive 0236.
Driver Mode Control 0244 (If Equipped).
2. Air Vents 0204.
3. Turn Signal Lever. See Turn and
Lane-Change Signals 0138.
Windshield Wiper/Washer 097.
4. Head-Up Display (HUD) 0123 (If
Equipped).
5. Instrument Cluster 0102.
6. Shift Lever. See Automatic Transmission
0 232.
Range Selection Mode. See Manual Mode
0 235.
7. Light Sensor. See Automatic Headlamp
System 0136.
8. Infotainment Controls. See Overview
0 144.
9. Climate Control Systems 0199 (If
Equipped).
Dual Automatic Climate Control System
0 201 (If Equipped).
10. Heated and Ventilated Front Seats 049
(If Equipped). 11.XPark Assist Switch (If Equipped). See
Assistance Systems for Parking or Backing
0 249.
gTraction Control/Electronic Stability
Control 0242.
|Hazard Warning Flashers 0137.
@Lane Departure Warning (LDW) 0262
(If Equipped).
5Hill Descent Control Switch (If
Equipped). See Hill Descent Control (HDC)
0 244.
jPower Assist Steps 026 (If
Equipped).
5Power Release Tailgate (If
Equipped). See Tailgate023.
ADC/AC Switch. See Power Outlets
0 98.
LExpress Window Down Button (If
Equipped). See Power Windows 038.
Tow/Haul Mode 0235 (On Some
Models).
Exhaust Brake (If Equipped). See Duramax
Diesel Supplement.
Power Take-Off (PTO) (If Equipped). See
Duramax Diesel Supplement. 12. Power Outlet (Alternating Current) (If
Equipped). See Power Outlets098.
13. Power Outlets 098.
14. USB Port 0153.
15. Wireless Charging 099 (If Equipped).
16. Trailer Brake Control Panel (If Equipped). See“Integrated Trailer Brake Control
System” underTowing Equipment 0276.
17. ENGINE START/STOP. See Ignition
Positions (Keyless Access) 0226 or
Ignition Positions (Key Access) 0224.
18. Steering Wheel Controls 096 (If
Equipped).
Driver Information Center (DIC) Controls.
See Driver Information Center (DIC) (Base
Level) 0119 or
Driver Information Center (DIC) (Midlevel
and Uplevel) 0120.
19. Horn 097.
20. Hood Release. See Hood0302.
21. Steering Wheel Adjustment 096 (Out
of View).
22. Cruise Control 0246.
Forward Collision Alert (FCA) System
0 257 (If Equipped).
Heated Steering Wheel 096 (If
Equipped).

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
22 Keys, Doors, and Windows
fully inserted. Remove the key and insert it
again. If this does not reset the lock, turn
the key halfway around in the cylinder and
repeat the reset procedure.
Power Door Locks
If equipped with power door locks.
Q:Press to lock the doors.
K:Press to unlock the doors.
Delayed Locking
If equipped, this feature delays the locking
of the doors until five seconds after all
doors are closed. Delayed locking can only be turned on when
the Open Door Anti-Lockout feature has
been turned off.
When
Qis pressed on the power door lock
switch while the door is open, a chime will
sound three times indicating delayed locking
is active.
The doors will lock automatically
five seconds after all doors are closed. If a
door is reopened before that time, the
five-second timer will reset when all doors
are closed again.
Press
Qon the door lock switch again or
press
Qon the RKE transmitter to lock the
doors immediately.
This feature can be programmed. See Vehicle
Personalization 0126.
Automatic Door Locks
If equipped, the doors will lock
automatically when all doors are closed, the
ignition is on, and the vehicle is shifted out
of P (Park). If a vehicle door is unlocked, and then
opened and closed, the doors will lock either
when your foot is removed from the brake
or the vehicle speed becomes faster than
13 km/h (8 mph).
To unlock the doors:
.PressKon the power door lock switch.
.Shift the transmission into P (Park).
Automatic door locking cannot be disabled.
Automatic door unlocking can be
programmed. See Vehicle Personalization
0 126.
Lockout Protection
If equipped, the ignition is on or in ACC/
ACCESSORY and the power door lock switch
is pressed with the driver door open, all the
doors will lock and only the driver door will
unlock.
If the vehicle is off and locking is requested
while a door is open, when all doors are
closed the vehicle will check to the Keyless
Access function (if equipped). If an RKE
transmitter is detected and the number of
RKE transmitters inside has not reduced, the
driver door will unlock and the horn will
chirp three times.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
122 Instruments and Controls
When the remaining oil life is low, the
CHANGE ENGINE OIL SOON message will
appear on the display. The oil should be
changed as soon as possible. SeeEngine Oil
0 305. In addition to the engine oil life
system monitoring the oil life, additional
maintenance is recommended. See
Maintenance Schedule 0384.
The Oil Life display must be reset after each
oil change. It will not reset itself. Do not
reset the Oil Life display at any time other
than when the oil has just been changed.
It cannot be reset accurately until the next
oil change. To reset, see Engine Oil Life
System 0307.
Tire Pressure : Shows the approximate
pressures of all four tires. Tire pressure is
displayed in either kilopascal (kPa) or in
pounds per square inch (psi). If the pressure
is low, the value for that tire is shown in
amber. See Tire Pressure Monitor System
0 342 and
Tire Pressure Monitor Operation 0343.
Air Filter Life : Shows an estimate of the
engine air filter’s remaining useful life and
the state of the system. Engine Air Filter Life
95% means 95% of the current air filter life
remains. Messages will display based on the
engine air filter life and the state of the system. When the REPLACE AT NEXT OIL
CHANGE message displays, the engine air
filter should be replaced at the time of the
next oil change. When the REPLACE SOON
message displays, the engine air filter
should be replaced at the earliest
convenience.
The Air Filter Life display must be reset after
the engine air filter replacement. To reset,
see
Engine Air Filter Life System 0308.
Brake Pad Life : This displays an estimate of
the remaining life of the front and rear
brake pads. Messages will display based on
brake pad wear and the state of the system.
Reset the Brake Pad Life display after
replacing the brake pads. See Brake Pad Life
System 0316.
Fuel Economy : Displays average fuel
economy, the best fuel economy over the
selected distance, and a bar graph showing
instantaneous fuel economy.
Press the thumbwheel to change the
selected distance. Press and hold the
thumbwheel while this display is active to
reset the best fuel economy and average
fuel economy. This display can also be reset
by selecting reset in the menu. Engine Hours (Hourmeter) :
Shows the total
number of hours the engine has run. This
display also shows the engine idle hours.
Transmission Fluid Temperature : Shows the
temperature of the automatic transmission
fluid in either degrees Celsius (°C) or degrees
Fahrenheit (°F).
Trailer Brake : On vehicles with the
Integrated Trailer Brake Control (ITBC)
system, the trailer brake display appears in
the DIC.
TRAILER GAIN shows the trailer gain setting.
This setting can be adjusted from 0.0 to 10.0
with either a trailer connected or
disconnected.
TRAILER OUTPUT shows the power output to
the trailer any time a trailer with electric
brakes is connected. Output is displayed as a
bar graph. Dotted lines may appear in the
OUTPUT display if a trailer is not connected.
Off Road : Displays vehicle pitch and roll
information, road wheel angle, and
four-wheel drive (4WD) status.
Follow Distance : If equipped, the current
follow time to the vehicle ahead is displayed
as a time value on this page.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
136 Lighting
.Driving on winding or hilly roads.
The automatic high-beam headlamps may
need to be disabled if any of the above
conditions exist.
Exterior Lamps Off Reminder
A reminder chime sounds when the
headlamps or parking lamps are manually
turned on, the ignition is off, and a door is
open. To disable the chime, turn the
lamps off.
Headlamp High/Low-Beam
Changer
Push the turn signal lever toward the
instrument panel to change the headlamps
from low to high beam.
Pull or push the turn signal lever to return
to low-beam headlamps.
When the high-beam headlamps are on, this
indicator light on the instrument cluster will
also be on.
Flash-to-Pass
This feature lets you use the high-beam
headlamps to signal a driver in front of you
that you want to pass. It works even if the
headlamps are in the automatic position.
To use it, pull the turn signal lever toward
you, then release it.
If the headlamps are in the automatic
position or on low beam, the high-beam
headlamps will turn on. Depending on the
type of headlamp, they will either turn off
after a short duration or stay on as long as
you hold the lever toward you. The
high-beam indicator on the instrument
cluster will come on. Release the lever to
return to normal operation.
Daytime Running Lamps (DRL)
DRL can make it easier for others to see the
front of the vehicle during the day. Fully
functional DRL are required on all vehicles
first sold in Canada. The DRL system comes on when the
following conditions are met:
.The ignition is on.
.The exterior lamp control is in AUTO.
.The transmission is not in P (Park).
.The light sensor determines it is daytime.
When the DRL system is on, only the DRL
are on. The taillamps, sidemarker lamps,
instrument panel lights, and other lamps
will not be on.
When it begins to get dark, the automatic
headlamp system switches from DRL to the
headlamps.
To turn off the DRL, turn the exterior lamp
control to
Oand then release. For vehicles
first sold in Canada, off will only work when
the vehicle is parked.
Automatic Headlamp System
When the exterior lamp control is set to
AUTO and it is dark enough outside, the
headlamps come on automatically.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
188 Infotainment System
2. Create a Personal Identification Number(PIN) by choosing a four-digit PIN.
Re-enter the PIN to confirm. To change
the PIN, touch Change PIN.
The PIN is required to:
.Register or unregister keys.
.Change Teen Driver settings.
.Change or clear the Teen Driver PIN.
.Access or delete Report Card data.
Register keys to activate Teen Driver and
assign restrictions to the key:
Any vehicle key can be registered, up to a
maximum of eight keys. Label the key to
tell it apart from the other keys.
For a pushbutton start system: 1. Start the engine.
2. For automatic transmissions, the vehicle must be in P (Park). For manual
transmissions, the vehicle must be
stopped with the parking brake set.
3. From the Settings menu, touch Vehicle and then Teen Driver.
4. Enter the PIN.
5. Place the Remote Keyless Entry (RKE) transmitter key you wish to register in
the transmitter pocket. The key does not need to be the one that started the
vehicle. See
Remote Keyless Entry (RKE)
System Operation (Key Access) 010 or
Remote Keyless Entry (RKE) System
Operation (Keyless Access) 013 for
transmitter pocket location.
6. From the Teen Driver menu, touch Setup Keys..If the transmitter key has not
previously been registered, the option
to add the key displays. Touch Setup
and a confirmation message displays.
Teen Driver restrictions will be
applied whenever this key is used to
operate the vehicle.
.If the transmitter key has already
been registered, the option to
remove the key displays. If Remove is
touched, the transmitter key is no
longer registered. A confirmation
message displays, and Teen Driver
restrictions will not be applied if this
transmitter key is used to operate
the vehicle.
In vehicles with a pushbutton start system,
if a Teen Driver and a non-Teen Driver key
are both present at start up, the vehicle will recognize the non-Teen Driver key to start
the vehicle. The Teen Driver settings will not
be active.
For a keyed ignition system:
1. Start the engine.
2. For automatic transmissions, the vehicle must be in P (Park). For manual
transmissions, the vehicle must be
stopped with the parking brake set.
3. From the Settings menu, touch Vehicle and then Teen Driver.
4. Enter the PIN.
5. Touch Setup Keys. The system displays instructions for registering or
unregistering a key. A confirmation
message displays.
Manage Settings
Audio Volume Limit : Allows the audio
volume limit to be turned on or off. Touch
Set Audio Volume Limit to choose the
maximum allowable audio volume level.
Set Audio Volume Limit : Allows a
maximum radio volume to be set. Use the
arrows to choose the maximum allowable
level for the audio volume.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
206 Driving and Operating
Driving and Operating
Driving Information
Driving for Better Fuel Economy . . . . . . 207
Distracted Driving . . . . . . . . . . . . . . . . . . . . . 207
Defensive Driving . . . . . . . . . . . . . . . . . . . . . 208
Impaired Driving . . . . . . . . . . . . . . . . . . . . . . 208
Control of a Vehicle . . . . . . . . . . . . . . . . . . . 208
Braking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
Steering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
Off-Road Recovery . . . . . . . . . . . . . . . . . . . . . 210
Loss of Control . . . . . . . . . . . . . . . . . . . . . . . . 210
Off-Road Driving . . . . . . . . . . . . . . . . . . . . . . . 211
Driving on Wet Roads . . . . . . . . . . . . . . . . . 214
Hill and Mountain Roads . . . . . . . . . . . . . . 215
Winter Driving . . . . . . . . . . . . . . . . . . . . . . . . . 215
If the Vehicle Is Stuck . . . . . . . . . . . . . . . . . 216
Vehicle Load Limits . . . . . . . . . . . . . . . . . . . . 217
Truck-Camper Loading Information . . . . . 222
Starting and Operating
New Vehicle Break-In . . . . . . . . . . . . . . . . . . 223
Ignition Positions (Key Access) . . . . . . . . 224
Ignition Positions (Keyless Access) . . . . . 226
Starting the Engine . . . . . . . . . . . . . . . . . . . . 227
Engine Heater . . . . . . . . . . . . . . . . . . . . . . . . . 228
Retained Accessory Power (RAP) . . . . . . . 229
Shifting Into Park . . . . . . . . . . . . . . . . . . . . . 230
Shifting out of Park . . . . . . . . . . . . . . . . . . . . 231
Parking over Things That Burn . . . . . . . . . 231Extended Parking . . . . . . . . . . . . . . . . . . . . . . 231
Engine Exhaust
Engine Exhaust . . . . . . . . . . . . . . . . . . . . . . . . 232
Running the Vehicle While Parked . . . . . 232
Automatic Transmission
Automatic Transmission . . . . . . . . . . . . . . . 232
Manual Mode . . . . . . . . . . . . . . . . . . . . . . . . . 235
Tow/Haul Mode . . . . . . . . . . . . . . . . . . . . . . . 235
Drive Systems
Four-Wheel Drive . . . . . . . . . . . . . . . . . . . . . . 236
Brakes
Antilock Brake System (ABS) . . . . . . . . . . 240
Electric Parking Brake . . . . . . . . . . . . . . . . . 240
Brake Assist . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
Hill Start Assist (HSA) . . . . . . . . . . . . . . . . . 242
Ride Control Systems
Traction Control/Electronic Stability
Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
Hill Descent Control (HDC) . . . . . . . . . . . . 244
Driver Mode Control . . . . . . . . . . . . . . . . . . 244
Limited-Slip Differential . . . . . . . . . . . . . . . . 245
Locking Rear Axle . . . . . . . . . . . . . . . . . . . . . 245
Cruise Control
Cruise Control . . . . . . . . . . . . . . . . . . . . . . . . . 246
Driver Assistance Systems
Driver Assistance Systems . . . . . . . . . . . . . 247
Assistance Systems for Parking or Backing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249
Assistance Systems for Driving . . . . . . . . 257
Forward Collision Alert (FCA) System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257
Automatic Emergency Braking (AEB) . . . . . . . . . . . . . . . . . . . . . . . . 259
Side Blind Zone Alert (SBZA) . . . . . . . . . . 260
Lane Change Alert (LCA) . . . . . . . . . . . . . . . 261
Lane Departure Warning (LDW) . . . . . . . 262
Fuel
Top Tier Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . 263
Recommended Fuel . . . . . . . . . . . . . . . . . . . . 263
Prohibited Fuels . . . . . . . . . . . . . . . . . . . . . . . 264
Fuels in Foreign Countries . . . . . . . . . . . . . 264
Fuel Additives . . . . . . . . . . . . . . . . . . . . . . . . . 264
E85 or FlexFuel . . . . . . . . . . . . . . . . . . . . . . . . 264
Filling the Tank (Pickup Model) . . . . . . . . 265
Filling the Tank (Chassis Cab and Box Delete Models) . . . . . . . . . . . . . . . . . . . . . . 266
Filling a Portable Fuel Container . . . . . . . 267
Trailer Towing
General Towing Information . . . . . . . . . . 268
Driving Characteristics and Towing Tips . . . . . . . . . . . . . . . . . . . . . . . . . 268
Trailer Towing . . . . . . . . . . . . . . . . . . . . . . . . . 272
Towing Equipment . . . . . . . . . . . . . . . . . . . . 276

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
212 Driving and Operating
Driving on Hills
Driving safely on hills requires good
judgment and an understanding of what the
vehicle can and cannot do.
{Warning
Many hills are simply too steep for any
vehicle. Driving up hills can cause the
vehicle to stall. Driving down hills can
cause loss of control. Driving across hills
can cause a rollover. You could be injured
or killed. Do not drive on steep hills.
Before driving on a hill, assess the
steepness, traction, and obstructions. If the
terrain ahead cannot be seen, get out of the
vehicle and walk the hill before driving
further.
When driving on hills:
.Use a low gear and keep a firm grip on
the steering wheel.
.Maintain a slow speed.
.When possible, drive straight up or down
the hill.
.Slow down when approaching the top of
the hill.
.Use headlamps even during the day to
make the vehicle more visible.
{Warning
Driving to the top of a hill at high speed
can cause a crash. There could be a
drop-off, embankment, cliff, or even
another vehicle. You could be seriously
injured or killed. As you near the top of a
hill, slow down and stay alert.
.Never go downhill forward or backward
with either the transmission or transfer
case in N (Neutral). The brakes could
overheat and you could lose control.
{Warning
If the vehicle has the two-speed
automatic transfer case, shifting the
transfer case to N (Neutral) can cause
your vehicle to roll even if the
transmission is in P (Park). This is because
the N (Neutral) position on the transfer
case overrides the transmission. You or
someone else could be injured. If leaving
the vehicle, set the parking brake and
shift the transmission to P (Park). Shift
the transfer case to any position but
N (Neutral).
.When driving down a hill, keep the
vehicle headed straight down. Use a low
gear because the engine will work with
the brakes to slow the vehicle and help
keep the vehicle under control.
{Warning
Heavy braking when going down a hill
can cause your brakes to overheat and
fade. This could cause loss of control and
you or others could be injured or killed.
Apply the brakes lightly when descending
a hill and use a low gear to keep vehicle
speed under control.
If a brake fade condition is detected, a DIC
warning message is displayed. Adjust brake
pedal use and shift to a lower transmission
gear to reduce braking.
If the brakes continue to fade to a severe
condition, additional DIC messages are
displayed. The brake system warning light
will illuminate, and the vehicle speed may
be limited. See Brake System Warning Light
0 113.
If the vehicle stalls on a hill: 1. Apply the brakes to stop the vehicle, and then apply the parking brake.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
232 Driving and Operating
Engine Exhaust{
Warning
Engine exhaust contains carbon monoxide
(CO), which cannot be seen or smelled.
Exposure to CO can cause
unconsciousness and even death.
Exhaust may enter the vehicle if:
.The vehicle idles in areas with poor
ventilation (parking garages, tunnels,
deep snow that may block underbody
airflow or tail pipes).
.The exhaust smells or sounds strange
or different.
.The exhaust system leaks due to
corrosion or damage.
.The vehicle exhaust system has been
modified, damaged, or improperly
repaired.
.There are holes or openings in the
vehicle body from damage or
aftermarket modifications that are not
completely sealed. (Continued)
Warning (Continued)
If unusual fumes are detected or if it is
suspected that exhaust is coming into the
vehicle:
.Drive it only with the windows
completely down.
.Have the vehicle repaired immediately.
Never park the vehicle with the engine
running in an enclosed area such as a
garage or a building that has no fresh air
ventilation.
Running the Vehicle While Parked
It is better not to park with the engine
running.
If the vehicle is left with the engine running,
follow the proper steps to be sure the
vehicle will not move. See Shifting Into Park
0 230 and
Engine Exhaust 0232.
If parking on a hill and pulling a trailer, see
Driving Characteristics and Towing Tips
0 268.
Automatic Transmission
If equipped, there is an electronic shift lever
position indicator within the instrument
cluster. This display comes on when the
ignition is in ACC/ACCESSORY, on or
service mode.
There are several different positions for the
shift lever.
See Driver Mode Control 0244 and “Range
Selection Mode” underManual Mode 0235.
P : This position locks the rear wheels. Use
P (Park) when starting the engine because
the vehicle cannot move easily.
When parked on a hill, especially when the
vehicle has a heavy load, you might notice
an increase in the effort to shift out of
P (Park). See “Torque Lock” underShifting
Into Park 0230.