
GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
440 Vehicle Care Steering, Suspension, and
Chassis Components Visually inspect steering,
suspension, and chassis
components for damaged, loose,
or missing parts or signs of wear at
least once a year.
Inspect power steering for proper
attachment, connections, binding,
leaks, cracks, chafing, etc.
Visually check constant velocity joint
boots and axle seals for leaks.
1500 Series vehicles, at least every
other oil change lubricate the outer
tie rod ends.
2500/3500 Series vehicles, at least
every other engine oil change
lubricate the upper and lower
control arm ball joints. Control arm
ball joints on 1500 series vehicles
are maintenance-free.
2500/3500 Series vehicles equipped
with steering linkage, at least every
other engine oil change lubricate the
tie rod ball joints, idler arm pivot
shaft bearings, idler arm socket, and
pitman arm socket. CautionLubrication of applicable steering/
suspension points should not be
done unless the temperature is
− 12 °C (10 °F) or higher,
or damage could result.
For an eAssist vehicle, see the
Silverado/Sierra eAssist
supplement.
Body Component Lubrication Lubricate all key lock cylinders,
hood hinges, liftgate hinges, and the
steel fuel door hinge unless the
components are plastic. Applying
silicone grease on weatherstrips
with a clean cloth will make them
last longer, seal better, and not stick
or squeak.
Underbody Maintenance
At least twice a year, spring and fall,
use plain water to flush any
corrosive materials from the
underbody. Take care to thoroughly
clean any areas where mud and other debris can collect. If equipped
with power assist steps, extend
them and then use a high pressure
wash to clean all joints and gaps.
Do not directly power wash the
transfer case and/or front/rear axle
output seals. High pressure water
can overcome the seals and
contaminate the fluid. Contaminated
fluid will decrease the life of the
transfer case and/or axles and
should be replaced.
Sheet Metal Damage If the vehicle is damaged and
requires sheet metal repair or
replacement, make sure the body
repair shop applies anti-corrosion
material to parts repaired or
replaced to restore corrosion
protection.
Original manufacturer replacement
parts will provide the corrosion
protection while maintaining the
vehicle warranty.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
444 Vehicle Care Care of Seat Belts Keep belts clean and dry.
{ WarningDo not bleach or dye seat belt
webbing. It may severely weaken
the webbing. In a crash, they
might not be able to provide
adequate protection. Clean and
rinse seat belt webbing only with
mild soap and lukewarm water.
Allow the webbing to dry.
Floor Mats
{ Warning
If a floor mat is the wrong size or
is not properly installed, it can
interfere with the pedals.
Interference with the pedals can
cause unintended acceleration
and/or increased stopping
distance which can cause a crash
(Continued) Warning (Continued) and injury. Make sure the floor
mat does not interfere with the
pedals.
Use the following guidelines for
proper floor mat usage:
.
The original equipment floor
mats were designed for your
vehicle. If the floor mats need
replacing, it is recommended
that GM certified floor mats be
purchased. Non-GM floor mats
may not fit properly and may
interfere with the pedals. Always
check that the floor mats do not
interfere with the pedals. .
Do not use a floor mat if the
vehicle is not equipped with a
floor mat retainer on the driver
side floor.
.
Use the floor mat with the
correct side up. Do not turn
it over.
.
Do not place anything on top of
the driver side floor mat.
.
Use only a single floor mat on
the driver side.
.
Do not place one floor mat on
top of another.
Removing and Replacing the
Floor Mats Pull up on the rear of the driver side
floor mat to unlock each retainer
and remove.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Service and Maintenance 449.
Check tire inflation pressures.
See Tire Pressure 0 397 .
.
Inspect tire wear. See Tire
Inspection 0 404 .
.
Visually check for fluid leaks.
.
Inspect engine air cleaner filter.
See Engine Air Cleaner/Filter
0 358 .
.
Inspect brake system. See
Exterior Care 0 435 .
.
Visually inspect steering,
suspension, and chassis
components for damaged, loose,
or missing parts or signs of wear
at least once a year. See
Exterior Care 0 435 . Lubricate
the suspension and steering
components at least every other
oil change. (If equipped with
grease fittings)
.
Check restraint system
components. See Safety System
Check 0 75 . .
Visually inspect fuel system for
damage or leaks.
.
Visually inspect exhaust system
and nearby heat shields for
loose or damaged parts.
.
Lubricate body components. See
Exterior Care 0 435 .
.
Check starter switch. See Starter
Switch Check 0 374 .
.
Check automatic transmission
shift lock control function. See
Automatic Transmission Shift
Lock Control Function Check
0 374 .
.
Check ignition transmission lock.
See Ignition Transmission Lock
Check 0 374 .
.
Check parking brake and
automatic transmission park
mechanism. See Park Brake and
P (Park) Mechanism Check
0 375 . .
Check accelerator pedal for
damage, high effort, or binding.
Replace if needed.
.
Visually inspect gas strut for
signs of wear, cracks, or other
damage. Check the hold open
ability of the strut. If the hold
open ability is low, service the
gas strut. See Gas Strut(s)
0 376 .
.
Inspect sunroof track and seal,
if equipped. See Sunroof 0 55 .
.
Verify spare tire key lock
operation and lubricate as
needed. See Tire Changing
0 415 .

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Service and Maintenance 457Usage Fluid/Lubricant
Front Axle – Four-Wheel Drive SAE 75W-90 Synthetic Axle Lubricant (GM Part No. 88900401, in
Canada 89021678).
Hydraulic Brake System DOT 3 Hydraulic Brake Fluid (GM Part No. 19353126, in
Canada 19299819).
Hydraulic Power Steering System
(2500/3500 Series Only) GM Power Steering Fluid (GM Part No. 19329450, in Canada 19329451).
Key Lock Cylinders, Hood Hinges,
Body Door Hinge Pins, Tailgate
Hinge and Linkage, Fuel Door Hinge,
Tailgate Handle Pivot Points, Hinges,
Latch Bolt, and Linkage Multi-Purpose Lubricant, Superlube (GM Part No. 12346241, in
Canada 10953474).
Rear Axle (1500 Series) SAE 75W-85 Synthetic Axle Lubricant (GM Part No. 19300457, in
Canada 19300458).
Rear Axle (2500/3500 Series) SAE 75W-90 Synthetic Axle Lubricant (GM Part No. 88900401, in
Canada 89021678).
Transfer Case (Four-Wheel Drive) DEXRON-VI Automatic Transmission Fluid.
Weatherstrip Conditioning Weatherstrip Lubricant (GM Part No. 3634770, in Canada 10953518) or
Dielectric Silicone Grease (GM Part No. 12345579, in Canada 10953481).
Weatherstrip Squeaks Synthetic Grease with Teflon, Superlube (GM Part No. 12371287, in
Canada 10953437).
Windshield Washer Automotive windshield washer fluid that meets regional freeze protection
requirements.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
470 Customer Information .
Lock-Out Service: Service to
unlock the vehicle if you are
locked out. A remote unlock may
be available if you have OnStar.
For security reasons, the driver
must present identification
before this service is given.
.
Emergency Tow from a Public
Road or Highway: Tow to the
nearest GMC dealer for warranty
service, or if the vehicle was in a
crash and cannot be driven.
Assistance is not given when the
vehicle is stuck in the sand,
mud, or snow.
.
Flat Tire Change: Service to
change a flat tire with the spare
tire. The spare tire, if equipped,
must be in good condition and
properly inflated. It is the owner's
responsibility for the repair or
replacement of the tire if it is not
covered by the warranty.
.
Battery Jump Start: Service to
jump start a dead battery. .
Trip Interruption Benefits and
Assistance: If your trip is
interrupted due to a warranty
event, incidental expenses may
be reimbursed within the
Powertrain warranty period.
Items considered are reasonable
and customary hotel, meals,
rental car, or a vehicle being
delivered back to the customer,
up to 500 miles.
Services Not Included in
Roadside Assistance .
Impound towing caused by
violation of any laws
.
Legal fines
.
Mounting, dismounting,
or changing of snow tires,
chains, or other traction devices
Service is not provided if a vehicle
is in an area that is not accessible
to the service vehicle or is not a
regularly traveled or maintained
public road, which includes ice and
winter roads. Off-road use is not
covered. Services Specific to
Canadian-Purchased Vehicles .
Fuel Delivery: Reimbursement
is up to 7 L. Diesel fuel delivery
may be restricted. Propane and
other fuels are not provided
through this service.
.
Lock-Out Service: Vehicle
registration is required.
.
Trip Interruption Benefits and
Assistance: Must be over
150 km from where your trip
was started to qualify.
Pre-authorization, original
detailed receipts, and a copy of
the repair orders are required.
Once authorization has been
received, the Roadside
Assistance advisor will help to
make arrangements and explain
how to receive payment.
.
Alternative Service: If
assistance cannot be provided
right away, the Roadside
Assistance advisor may give
permission to get local
emergency road service. You will
receive payment, up to $100,

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Customer Information 477
Reporting Safety Defects
to General Motors In addition to notifying NHTSA (or
Transport Canada) in a situation like
this, notify General Motors.
Call 1-800-GMC-8782
(1-800-462-8782), or write:
GMC Customer Assistance Center
P.O. Box 33172
Detroit, MI 48232-5172
In Canada, call 1-800-263-3777
(English) or 1-800-263-7854
(French), or write:
General Motors of Canada
Company
Customer Care Centre,
Mail Code: CA1-163-005
1908 Colonel Sam Drive
Oshawa, Ontario L1H 8P7
In Mexico, call 01-800-466-0801.
In other Central America and
Caribbean Countries, call
52-722-236-0680. Vehicle Data
Recording and
Privacy The vehicle has a number of
computers that record information
about the vehicle ’ s performance and
how it is driven. For example, the
vehicle uses computer modules to
monitor and control engine and
transmission performance, to
monitor the conditions for airbag
deployment and deploy them in a
crash, and, if equipped, to provide
antilock braking to help the driver
control the vehicle. These modules
may store data to help the dealer
technician service the vehicle.
Some modules may also store data
about how the vehicle is operated,
such as rate of fuel consumption or
average speed. These modules may
retain personal preferences, such as
radio presets, seat positions, and
temperature settings. Event Data Recorders This vehicle is equipped with an
event data recorder (EDR). The
main purpose of an EDR is to
record, in certain crash or near
crash-like situations, such as an air
bag deployment or hitting a road
obstacle, data that will assist in
understanding how a vehicle ’ s
systems performed. The EDR is
designed to record data related to
vehicle dynamics and safety
systems for a short period of time,
typically 30 seconds or less. The
EDR in this vehicle is designed to
record such data as:
.
How various systems in your
vehicle were operating;
.
Whether or not the driver and
passenger safety belts were
buckled/fastened;
.
How far (if at all) the driver was
depressing the accelerator and/
or brake pedal; and,
.
How fast the vehicle was
traveling.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
OnStar 481
Security If equipped, OnStar provides these
services:
.
With Stolen Vehicle Assistance,
OnStar Advisors can use GPS to
pinpoint the vehicle and help
authorities quickly recover it.
.
With Remote Ignition Block,
if equipped, OnStar can block
the engine from being restarted.
.
With Stolen Vehicle Slowdown,
if equipped, OnStar can work
with law enforcement to
gradually slow the vehicle down.
Theft Alarm Notification If equipped, if the doors are locked
and the vehicle alarm sounds, a
notification by text, e-mail, or phone
call will be sent. If the vehicle is
stolen, an OnStar Advisor can work
with authorities to recover the
vehicle.
Navigation OnStar navigation requires a
specific OnStar service plan. Press
Q to receive Turn-by-Turn
directions or have them sent to the
vehicle ’ s navigation screen,
if equipped.
Turn-by-Turn Navigation 1. Press
Q to connect to an
Advisor.
2. Request directions to be
downloaded to the vehicle.
3. Follow the voice-guided
commands.
Using Voice Commands
During a Planned Route Functionality of the Voice Command
button may vary by vehicle and
region. For some vehicles, press
=to open the OnStar app on the
infotainment display. For other
vehicles press
= as follows.
Cancel Route
1. Press
= . System responds:
“ OnStar ready, ” then a tone. 2. Say “ Cancel route. ” System
responds: “ Do you want to
cancel directions? ”
3. Say “ Yes. ” System responds:
“ OK, request completed, thank
you, goodbye. ”
Route Preview
1. Press
= . System responds:
“ OnStar ready, ” then a tone.
2. Say “ Route preview. ” System
responds with the next three
maneuvers.
Repeat
1. Press
= . System responds:
“ OnStar ready, ” then a tone.
2. Say “ Repeat. ” System
responds with the last direction
given, then responds with
“ OnStar ready, ” then a tone.
Get My Destination
1. Press
= . System responds:
“ OnStar ready, ” then a tone.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
OnStar 483OnStar Advisor. On some vehicles,
Wi-Fi can also be managed from the
Wi-Fi Hotspot menu.
MyGMC Mobile App (If Available)
Download the myGMC mobile app
to compatible Apple and Android
smartphones. GMC users can
access the following services from a
smartphone:
.
Remotely start/stop the vehicle,
if factory-equipped.
.
Lock/unlock doors, if equipped
with automatic locks.
.
Activate the horn and lamps.
.
Check the vehicle ’ s fuel level, oil
life, or tire pressure,
if factory-equipped with the Tire
Pressure Monitor System.
.
Send destinations to the vehicle.
.
Locate the vehicle on a map
(U.S. market only).
.
Turn the vehicle's Wi-Fi hotspot
on/off, manage settings, and
monitor data consumption,
if equipped. .
Locate a dealer and schedule
service.
.
Request roadside assistance.
.
Set a parking reminder with pin
drop, take a photo, make a note,
and set a timer.
.
Connect with GMC on social
media.
For myGMC mobile app information
and compatibility, see
www.my.gmc.com.
An active OnStar service,
compatible device, factory-installed
remote start, and power locks are
required. Data rates apply. See
onstar.com for details and system
limitations.
Remote Services Contact an OnStar Advisor to
unlock the doors or sound the horn
and flash the lamps. OnStar AtYourService OnStar Advisors can provide offers
from restaurants and retailers on
your route, help locate hotels,
or book a room. These services
vary by market.
OnStar Hands-Free Calling Make and receive calls with the
built-in wireless calling service,
which requires available minutes.
Functionality of the Voice Command
button may vary by vehicle and
region. For some vehicles, press
= to open the OnStar app on the
infotainment display, then select
Hands-Free calling. For other
vehicles press
= as follows.
Make a Call
1. Press
= . System responds:
“ OnStar ready. ”
2. Say “ Call. ” System responds:
“ Call. Please say the name or
number to call. ”