
GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 5/3/16
246 Driving and Operating
Traction is reduced on hard packed
snow and ice and it is easy to lose
control. Reduce vehicle speed when
driving on hard packed snow
and ice.
{Warning
Driving on frozen lakes, ponds,
or rivers can be dangerous. Ice
conditions vary greatly and the
vehicle could fall through the ice;
you and your passengers could
drown. Drive your vehicle on safe
surfaces only.
Driving in Water
{Warning
Driving through rushing water can
be dangerous. Deep water can
sweep your vehicle downstream
and you and your passengers
could drown. If it is only shallow
water, it can still wash away the
ground from under your tires.(Continued)
Warning (Continued)
Traction could be lost, and the
vehicle could roll over. Do not
drive through rushing water.
Caution
Do not drive through standing
water if it is deep enough to cover
the wheel hubs, axles, or exhaust
pipe. Deep water can damage the
axle and other vehicle parts.
If the standing water is not too deep,
drive slowly through it. At faster
speeds, water splashes and the
vehicle can stall. When going
through water, the brakes get wet
and it may take longer to stop. See
“Driving on Wet Roads” later in this
section.
After Off-Road Driving
Remove any brush or debris that
has collected on the underbody or
chassis, or under the hood. These
accumulations can be a fire hazard.
After operation in mud or sand,
have the brake linings cleaned and
checked. These substances can
cause glazing and uneven braking.
Check the body structure, steering,
suspension, wheels, tires, and
exhaust system for damage and
check the fuel lines and cooling
system for any leakage.
More frequent maintenance service
is required. See the Maintenance
Schedule 0438.
Driving on Wet Roads
Rain and wet roads can reduce
vehicle traction and affect your
ability to stop and accelerate.
Always drive slower in these types
of driving conditions and avoid
driving through large puddles and
deep-standing or flowing water.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 5/3/16
Driving and Operating 307
If parking the rig on a hill:1. Press the brake pedal, but do not shift into P (Park) yet. Turn
the wheels into the curb if
facing downhill or into traffic if
facing uphill.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, release the regular
brakes until the chocks absorb
the load.
4. Reapply the brake pedal. Then apply the parking brake and
shift into P (Park).
5. Release the brake pedal.
Leaving After Parking on a Hill
1. Apply and hold the brake pedal.
2. Start the engine.
3. Shift into a gear.
4. Release the parking brake.
5. Let up on the brake pedal.
6. Drive slowly until the trailer is clear of the chocks. 7. Stop and have someone pick
up and store the chocks.
Maintenance when Trailer
Towing
The vehicle needs service more
often when pulling a trailer. See
Maintenance Schedule 0438.
Things that are especially important
in trailer operation are automatic
transmission fluid, engine oil, axle
lubricant, belts, cooling system, and
brake system. It is a good idea to
inspect these before and during
the trip.
Check periodically to see that all
hitch nuts and bolts are tight.
Trailer Towing
If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
If the vehicle is bi-fuel, see the
bi-fuel supplement.
Do not tow a trailer during break-in.
See New Vehicle Break-In 0258.
{Warning
The driver can lose control when
pulling a trailer if the correct
equipment is not used or the
vehicle is not driven properly. For
example, if the trailer is too heavy
or the trailer brakes are
inadequate for the load, the
vehicle may not stop as expected.
The driver and passengers could
be seriously injured. The vehicle
may also be damaged; the
resulting repairs would not be
covered by the vehicle warranty.
Pull a trailer only if all the steps in
this section have been followed.
Ask your dealer for advice and
information about towing a trailer
with the vehicle.
Caution
Pulling a trailer improperly can
damage the vehicle and result in
costly repairs not covered by the
(Continued)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 5/3/16
334 Driving and Operating
Conversions and
Add-Ons
Add-On Electrical
Equipment
{Warning
The Data Link Connector (DLC) is
used for vehicle service and
Emission Inspection/Maintenance
testing. SeeMalfunction Indicator
Lamp (Check Engine Light)
0 133. A device connected to the
DLC —such as an aftermarket
fleet or driver-behavior tracking
device —may interfere with
vehicle systems. This could affect
vehicle operation and cause a
crash. Such devices may also
access information stored in the
vehicle’s systems.
Caution
Some electrical equipment can
damage the vehicle or cause
components to not work and
would not be covered by the
vehicle warranty. Always check
with your dealer before adding
electrical equipment.
Add-on equipment can drain the
vehicle's 12-volt battery, even if the
vehicle is not operating.
The vehicle has an airbag system.
Before attempting to add anything
electrical to the vehicle, see
Servicing the Airbag-Equipped
Vehicle 079 and Adding Equipment
to the Airbag-Equipped
Vehicle 079.
For information on wiring auxiliary
switches, see www.gmupfitter.com
or contact your dealer.
Adding a Snow Plow or
Similar Equipment
Caution
Do not exceed 72 km/h (45 mph)
with a snow plow mounted to the
vehicle. The vehicle could
overheat and be damaged.
Before installing a snow plow on the
vehicle, follow these guidelines:
Caution
If the vehicle does not have the
snow plow prep package, RPO
VYU, adding a plow can damage
the vehicle, and the repairs would
not be covered by the vehicle
warranty. Unless the vehicle was
built to carry a snow plow, do not
add one to the vehicle. If the
vehicle has RPO VYU, then the
payload the vehicle can carry will
be reduced when a snow plow is
installed. The vehicle can be (Continued)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 5/3/16
342 Vehicle Care
Vehicle Checks
Doing Your Own
Service Work
{Warning
It can be dangerous to work on
your vehicle if you do not have
the proper knowledge, service
manual, tools, or parts. Always
follow owner manual procedures
and consult the service manual
for your vehicle before doing any
service work.
If doing some of your own service
work, use the proper service
manual. It tells you much more
about how to service the vehicle
than this manual can. To order the
proper service manual, see Service
Publications Ordering
Information 0466.
This vehicle has an airbag system.
Before attempting to do your own
service work, see Servicing the
Airbag-Equipped Vehicle 079. Keep a record with all parts receipts
and list the mileage and the date of
any service work performed. See
Maintenance Records
0451.
Caution
Even small amounts of
contamination can cause damage
to vehicle systems. Do not allow
contaminants to contact the fluids,
reservoir caps, or dipsticks.
Hood
To open the hood:
1. Pull the handle with this symbol
on it. It is inside the vehicle
under the steering wheel.
2. Go to the front of the vehicle tofind the secondary hood
release. The handle is under
the front edge of the hood near
the center. Push the handle to
the right and at the same time
raise the hood.
Before closing the hood, be sure all
the filler caps are on properly. Then
bring the hood from full open to
within 15 cm (6 in) from the closed
position, pause, and push the front
center of the hood with a swift, firm
motion to fully close the hood.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 5/3/16
352 Vehicle Care
If the vehicle has a CHANGE
ENGINE OIL SOON message and it
comes back on when the vehicle is
started and/or the OIL LIFE
REMAINING is near 0%, the engine
oil life system has not been reset.
Repeat the procedure.
Automatic Transmission
Fluid (6 Speed
Transmission)
When to Check and Change
Automatic Transmission Fluid
It is usually not necessary to check
the transmission fluid level. The only
reason for fluid loss is a
transmission leak or overheated
transmission. If a small leak is
suspected, then use the following
checking procedures to check the
fluid level. However, if there is a
large leak, then it may be necessary
to have the vehicle towed to a
dealer service department and have
it repaired before driving the vehicle
further.
Caution
Use of the incorrect automatic
transmission fluid may damage
the vehicle, and the damage may
not be covered by the vehicle
warranty. Always use the
automatic transmission fluid listed
inRecommended Fluids and
Lubricants 0447.
Change the fluid and filter at the
scheduled maintenance intervals
listed in Maintenance Schedule
0 438. Be sure to use the
transmission fluid listed in
Recommended Fluids and
Lubricants 0447.
How to Check Automatic
Transmission Fluid
Caution
Too much or too little fluid can
damage the transmission. Too
much can mean that some of the (Continued)
Caution (Continued)
fluid could come out and fall on
hot engine parts or exhaust
system parts, starting a fire. Too
little fluid could cause the
transmission to overheat. Be sure
to get an accurate reading if
checking the transmission fluid.
Before checking the fluid level,
prepare the vehicle: 1. Start the engine and park the vehicle on a level surface.
Keep the engine running.
2. Apply the parking brake and place the shift lever in P (Park).
3. With your foot on the brake pedal, move the shift lever
through each gear range,
pausing for about
three seconds in each range.
Then, move the shift lever back
to P (Park).

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 5/3/16
Vehicle Care 355
equipped with a transmission fluid
level dipstick. There is a special
procedure for checking and
changing the transmission fluid in
these vehicles. Because this
procedure is difficult, this should be
done at the dealer. Contact the
dealer for additional information or
the procedure can be found in the
service manual. SeeService
Publications Ordering
Information 0466.
Caution
Use of the incorrect automatic
transmission fluid may damage
the vehicle, and the damage may
not be covered by the vehicle
warranty. Always use the
automatic transmission fluid listed
in Recommended Fluids and
Lubricants 0447.
Change the fluid and filter at the
scheduled maintenance intervals
listed in Maintenance Schedule
0 438. Be sure to use the transmission fluid listed in
Recommended Fluids and
Lubricants
0447.
Engine Air Cleaner/Filter
If the vehicle has a diesel engine,
see “8-Cylinder Pickup Models”
under “Engine Air Cleaner/Filter” in
the Duramax diesel supplement for
the correct inspection and
replacement procedures.
The engine air cleaner/filter is on
the passenger side of the engine
compartment. See Engine
Compartment Overview 0343.
When to Inspect the Engine Air
Cleaner/Filter
For intervals on changing and
inspecting the engine air filter, see
Maintenance Schedule 0438.
How to Inspect the Engine Air
Cleaner/Filter
Do not start the engine or have the
engine running with the engine air
cleaner/filter housing open. Before
removing the engine air cleaner/
filter, make sure that the engine air cleaner/filter housing and nearby
components are free of dirt and
debris. Remove the engine air
cleaner/filter. Lightly tap and shake
the engine air cleaner/filter (away
from the vehicle), to release loose
dust and dirt. Inspect the engine air
cleaner/filter for damage, and
replace if damaged. Do not clean
the engine air cleaner/filter or
components with water or
compressed air.
To inspect or replace the engine air
cleaner/filter:
1. Screws
2. Electrical Connectors

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 5/3/16
366 Vehicle Care
{Warning
If too much brake fluid is added, it
can spill on the engine and burn,
if the engine is hot enough. You
or others could be burned, and
the vehicle could be damaged.
Add brake fluid only when work is
done on the brake hydraulic
system.
When the brake fluid falls to a low
level, the brake warning light comes
on. See Brake System Warning
Light 0134.
Brake fluid absorbs water over time.
Replace brake fluid at the specified
intervals to prevent increased
stopping distance. See Maintenance
Schedule 0438.
Checking Brake Fluid
Check brake fluid by looking at the
brake fluid reservoir. See Engine
Compartment Overview 0343.
The fluid level should be above
MIN. If it is not, have the brake
hydraulic system checked to see if
there is a leak.
After work is done on the brake
hydraulic system, make sure the
level is above MIN but not over the
MAX mark.
What to Add
Use only GM approved DOT 3
brake fluid from a clean, sealed
container. See Recommended
Fluids and Lubricants 0447.
{Warning
The wrong or contaminated brake
fluid could result in damage to the
brake system. This could result in
the loss of braking leading to a
possible injury. Always use the
proper GM approved brake fluid.
Caution
If brake fluid is spilled on the
vehicle's painted surfaces, the
paint finish can be damaged.
Immediately wash off any painted
surface.
Battery - North America
The original equipment battery is
maintenance free. Do not remove
the cap and do not add fluid.
Refer to the replacement number
shown on the original battery label
when a new battery is needed. See
Engine Compartment Overview
0343 for battery location.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 5/3/16
Vehicle Care 367
{Warning
WARNING:Battery posts,
terminals, and related
accessories contain lead and lead
compounds, chemicals known to
the State of California to cause
cancer and birth defects or other
reproductive harm. Batteries also
contain other chemicals known to
the State of California to cause
cancer. WASH HANDS AFTER
HANDLING.
See California Proposition
65 Warning 0340.
Vehicle Storage
{Warning
Batteries have acid that can burn
you and gas that can explode.
You can be badly hurt if you are
not careful. See Jump Starting -
North America 0418 for tips on
working around a battery without
getting hurt. Infrequent Usage: Remove the
black, negative (−) cable from the
battery to keep the battery from
running down.
Extended Storage: Remove the
black, negative (−) cable from the
battery or use a battery trickle
charger.
Four-Wheel Drive
Transfer Case
When to Check Lubricant
Refer to
Maintenance Schedule
0 438 to determine when to check
the lubricant.
1. Fill Plug
2. Drain Plug
To get an accurate reading, the
vehicle should be on a level
surface.
If the level is below the bottom of
the fill plug (1) hole, located on the
transfer case, some lubricant will
need to be added. Add enough
lubricant to raise the level to the
bottom of the fill plug (1) hole. Use
care not to overtighten the plug.
When to Change Lubricant
Refer to Maintenance Schedule
0 438 to determine how often to
change the lubricant.
What to Use
Refer to Recommended Fluids and
Lubricants 0447 to determine what
kind of lubricant to use.