GMC SIERRA DENALI 2015 Owners Manual

Black plate (30,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
10-30 Vehicle Care 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 on
page 11-3 to determine how often to
change the lubricant.
What to Use
Refer to Recommended Fluids and
Lubricants on page 11-12 to
determine what kind of lubricant
to use. Front Axle When to Check and Change
Lubricant
It is not necessary to regularly
check front axle fluid unless a leak
is suspected, or an unusual noise is
heard. A fluid loss could indicate a
problem. Have it inspected and
repaired.
How to Check Lubricant
To get an accurate reading, the
vehicle should be on a level
surface. 1500 Series
1. Fill Plug
2. Drain Plug

Black plate (31,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-31
All Except 1500 Series
1. Fill Plug
2. Drain Plug .
When the differential is cold, add
enough lubricant to raise the
level from 0 mm (0 in) to 3.2 mm
(1/8 in) below the fill
plug (1) hole. .
When the differential is at
operating temperature (warm),
add enough lubricant to raise the
level to the bottom of the fill
plug (1) hole. What to Use
Refer to Recommended Fluids and
Lubricants on page 11-12 to
determine what kind of lubricant
to use.
Rear Axle When to Check Lubricant It is not necessary to regularly
check rear axle fluid unless a leak is
suspected or an unusual noise is
heard. A fluid loss could indicate a
problem. Have it inspected and
repaired.
All axle assemblies are filled by
volume of fluid during production.
They are not filled to reach a certain
level. When checking the fluid level
on any axle, variations in the
readings can be caused by factory
fill differences between the minimum
and the maximum fluid volume. Also, if a vehicle has just been
driven before checking the fluid
level, it may appear lower than
normal because fluid has traveled
out along the axle tubes and has
not drained back to the sump area.
Therefore, a reading taken
five minutes after the vehicle has
been driven will appear to have a
lower fluid level than a vehicle that
has been stationary for an hour or
two. Remember that the rear axle
assembly must be supported to get
a true reading.

Black plate (32,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
10-32 Vehicle Care How to Check Lubricant
2500HD with 6.0L
All Other Series and Engines To get an accurate reading, the
vehicle should be on a level
surface. .
For 6.2L 1500 Series
applications, the proper level is
from 15 mm to 40 mm (0.6 in to
1.6 in) below the bottom of the
fill plug hole, located on the rear
axle. Add only enough fluid to
reach the proper level. .
For all 6.0L 2500HD Series
applications, the proper level is
from 0 mm to 13 mm (0 to 0.5 in)
below the bottom of the fill plug
hole, located on the rear axle.
Add only enough fluid to reach
the proper level. .
For all 6.6L Duramax Diesel
2500HD Series applications and
all 3500 Series applications, the
proper level is from 17 mm to
21 mm (0.6 in to 0.8 in) below
the bottom of the fill plug hole,
located on the rear axle. Add
only enough fluid to reach the
proper level. What to Use Refer to Recommended Fluids and
Lubricants on page 11-12 to
determine what kind of lubricant
to use.
Noise Control System The following information relates to
compliance with federal noise
emission standards for vehicles with
a Gross Vehicle Weight Rating
(GVWR) of more than 4 536 kg
(10,000 lb). The noise control
system warranty is given in your
warranty manual.
These standards apply only to
vehicles sold in the United States.
Federal law prohibits the following
acts or the causing thereof:
1. The removal or rendering
inoperative by any person, other
than for purposes of
maintenance, repair or
replacement, of any device or
element of design incorporated
into any new vehicle for the

Black plate (33,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-33purpose of noise control, prior to
its sale or delivery to the ultimate
purchaser or while it is in use; or
2. The use of the vehicle after such
device or element of design has
been removed or rendered
inoperative by any person.
Among those acts presumed to
constitute tampering are the acts
listed below.
Insulation:
Removal of the noise shields or any
underhood insulation.
Engine:
Removal or rendering engine speed
governor, if the vehicle has one,
inoperative so as to allow engine
speed to exceed manufacturer
specifications. Fan and Drive: .
Removal of fan clutch, if the
vehicle has one, or rendering
clutch inoperative. .
Removal of the fan shroud, if the
vehicle has one.
Air Intake: .
Removal of the air cleaner
silencer. .
Modification of the air cleaner.
Exhaust: .
Removal of the muffler and/or
resonator. .
Removal of the exhaust pipes
and exhaust pipe clamps. Starter Switch Check
{ WarningWhen you are doing this
inspection, the vehicle could
move suddenly. If the vehicle
moves, you or others could be
injured.
1. Before starting this check, be
sure there is enough room
around the vehicle.
2. Apply both the parking brake
and the regular brake.
Do not use the accelerator
pedal, and be ready to turn off
the engine immediately if it
starts.
3. Try to start the engine in each
gear. The vehicle should start
only in P (Park) or N (Neutral).
If the vehicle starts in any other
position, contact your dealer for
service.

Black plate (34,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
10-34 Vehicle Care
Automatic Transmission
Shift Lock Control
Function Check
{ WarningWhen you are doing this
inspection, the vehicle could
move suddenly. If the vehicle
moves, you or others could be
injured.
1. Before starting this check, be
sure there is enough room
around the vehicle. It should be
parked on a level surface.
2. Apply the parking brake. Be
ready to apply the regular brake
immediately if the vehicle begins
to move.
3. With the engine off, turn the
ignition on, but do not start the
engine. Without applying the
regular brake, try to move the
shift lever out of P (Park) with normal effort. If the shift lever
moves out of P (Park), contact
your dealer for service.
Ignition Transmission
Lock Check While parked and with the parking
brake set, try to turn the ignition to
LOCK/OFF in each shift lever
position. .
The ignition should turn to
LOCK/OFF only when the shift
lever is in P (Park). .
The ignition key should come
out only in LOCK/OFF.
Contact your dealer if service is
required. Park Brake and P (Park)
Mechanism Check
{ WarningWhen you are doing this check,
the vehicle could begin to move.
You or others could be injured
and property could be damaged.
Make sure there is room in front
of the vehicle in case it begins to
roll. Be ready to apply the regular
brake at once should the vehicle
begin to move.
Park on a fairly steep hill, with the
vehicle facing downhill. Keeping
your foot on the regular brake, set
the parking brake. .
To check the parking brake's
holding ability: With the engine
running and the transmission in
N (Neutral), slowly remove foot
pressure from the regular brake
pedal. Do this until the vehicle is
held by the parking brake only.

Black plate (35,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-35.
To check the P (Park)
mechanism's holding ability:
With the engine running, shift to
P (Park). Then release the
parking brake followed by the
regular brake.
Contact your dealer if service is
required.
Wiper Blade Replacement Windshield wiper blades should be
inspected for wear or cracking.
Replacement blades come in
different types and are removed in
different ways. For proper
windshield wiper blade length and
type, see Maintenance
Replacement Parts on page 11-14 .
{ Caution
Allowing the wiper arm to touch
the windshield when no wiper
blade is installed could damage
the windshield. Any damage that
(Continued) Caution (Continued) occurs would not be covered by
your warranty. Do not allow the
wiper arm to touch the windshield.
To replace the windshield wiper
blade:
1. Pull the windshield wiper
assembly away from the
windshield. 2. Press the button (2) in the
middle of the wiper arm
connector, and pull the wiper
blade away from the arm
connector (1).
3. Remove the wiper blade.
4. Reverse Steps 1 – 3 for wiper
blade replacement.
Glass Replacement If the windshield or front side glass
must be replaced, see your dealer
to determine the correct
replacement glass.

Black plate (36,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
10-36 Vehicle Care
Headlamp Aiming Headlamp aim has been preset and
should need no further adjustment.
If the vehicle is damaged in a crash,
the headlamp aim may be affected.
If adjustment to the headlamps is
necessary, see your dealer.
Bulb Replacement For the proper type of replacement
bulbs, see Replacement Bulbs on
page 10-40 .
For any bulb ‐ changing procedure
not listed in this section, contact
your dealer.
Halogen Bulbs
{ WarningHalogen bulbs have pressurized
gas inside and can burst if you
drop or scratch the bulb. You or
others could be injured. Be sure
to read and follow the instructions
on the bulb package.
LED Lighting This vehicle has several LED lamps.
For replacement of any LED lighting
assembly, contact your dealer. Headlamps, Front Turn
Signal, Sidemarker, and
Parking Lamps
Driver Side
1. Front Turn Signal/
Sidemarker/Parking Lamp
2. High/Low-Beam Headlamp
See your dealer for passenger side
replacement.
Headlamp
1. Open the hood.

Black plate (37,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-372. Remove the headlamp bulb
assembly cover by turning it
counterclockwise.
3. Turn the bulb socket
counterclockwise to remove it
from the headlamp assembly
and pull it straight out.
4. Unplug the electrical connector
from the old bulb by releasing
the clip on the bulb socket.
Turn Signal/Sidemarker/
Parking Lamp 1. Open the hood.
2. If replacing a bulb on the
passenger side, remove the
engine air cleaner.
3. Turn the bulb socket
counterclockwise to remove it
from the headlamp assembly
and pull it straight out.
4. Remove the bulb by pulling it
straight out of the bulb socket. Fog Lamps To replace the front fog lamp bulb:
1. Locate the fog lamp under the
front bumper.
2. Disconnect the electrical
connector from the fog lamp bulb
assembly by pressing the
connector release.
3. Remove the bulb from the
housing by squeezing the two
release tabs and pulling it
straight out of the assembly. Taillamps, Turn Signal,
Stoplamps, and Back-Up
Lamps
Single Rear Wheel Lamp Shown,
Dual Rear Wheel Lamp Similar
1. Stoplamp/Taillamp/Turn
Signal Lamp
2. Back-Up Lamp
3. Sidemarker Lamp
To replace one of these bulbs:
1. Open the tailgate.

Black plate (38,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
10-38 Vehicle Care
2. Remove the two rear lamp
assembly screws.
3. Pull the rear lamp assembly
outboard away from the box side
until the retainers release. There
will be a noise when the
retainers release. 4. Pull the rear lamp assembly
straight back to remove it from
the vehicle.
5. Turn the bulb socket
counterclockwise. 6. Pull the bulb straight out from
the socket.
7. Replace the bulb, then insert the
bulb socket into the rear lamp
assembly and turn clockwise.
8. Verify the retainer ring is in the
proper position. If the retainer
ring is out of position, it will not
engage. Reset the retainer by
pulling it forward with a tool.

Black plate (39,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-39
9. Push the rear lamp assembly
straight in until it is seated
against the vehicle.
10. Make sure the rear lamp
assembly is flush with the
box side.
11. Reinstall the two rear lamp
assembly screws. Center High-Mounted
Stoplamp (CHMSL) and
Cargo Lamp
1. Cargo Lamp Bulbs
2. Center High-Mounted
Stoplamp (CHMSL) Bulb To replace one of these bulbs:
1. Remove the two screws and lift
off the lamp assembly.
2. Turn the bulb socket
counterclockwise and pull it
straight out.
3. Pull the bulb straight out from
the socket.