Page 409 of 528

Black plate (31,1)GMC Yukon/Yukon XL Owner Manual - 2011
Vehicle Care 10-31
What to Use
Refer toRecommended Fluids
and Lubricants on page 11‑7 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 there
is a leak 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.How to Check Lubricant
1500 Series
2500 Series
To get an accurate reading, the
vehicle should be on a level
surface.
.For the 1500 series, the proper
level is from 1.0 mm to 19.0 mm
(0.04 in to 0.75 in) below the
bottom of the fill plug hole,
located on the rear axle. Add
only enough fluid to reach the
proper level.
Page 410 of 528

Black plate (32,1)GMC Yukon/Yukon XL Owner Manual - 2011
10-32 Vehicle Care
.For the 2500 series, the proper
level is from 0 mm to 13 mm
(0 in to 1/2 in) below the bottom
of the fill plug hole, located at
the front of the axle. Add only
enough fluid to reach the proper
level.
Starter Switch Check
{WARNING
When 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. Firmly apply both the parking
brake and the regular brake.
See Parking Brake on
page 9‑51.
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.
Automatic Transmission
Shift Lock Control
Function Check
{WARNING
When 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. Firmly apply the parking brake. See Parking Brake on
page 9‑51.
Be ready to apply the regular
brake immediately if the vehicle
begins to move.
Page 411 of 528

Black plate (33,1)GMC Yukon/Yukon XL Owner Manual - 2011
Vehicle Care 10-33
3. With the engine off, turn theignition 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
{WARNING
When 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.
.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.
See Scheduled Maintenance on
page 11‑2.
Replacement blades come in
different types and are removed in
different ways.
Front Wiper Blade
Replacement
1. Pull the windshield wiper arm connector away from the
windshield.
Page 412 of 528

Black plate (34,1)GMC Yukon/Yukon XL Owner Manual - 2011
10-34 Vehicle Care
2. Squeeze the grooved areas oneach side of the blade, and turn
the blade assembly away from
the arm connector.
3. Install the new blade onto thearm connector and make sure
the grooved areas are fully set in
the locked position.
For the proper type and size, see
Maintenance Replacement Parts on
page 11‑9.
Rear Wiper Blade Replacement
1. Lift the wiper blade assembly up and out of the park rest position.
2. Pull the wiper blade assemblyaway from the backglass. The
backglass wiper blade will not
lock in a vertical position, so
care should be used when
pulling it away from the vehicle.
3. Turn the wiper blade assembly, and pull it off of the wiper arm.
Hold the wiper arm in position
and push the blade away from
the wiper arm.
4. Replace the wiper blade.
5. Return the wiper blade assemblyto the park rest position.
Glass Replacement
If the windshield or front side
glass must be replaced, see your
dealer to determine the correct
replacement glass.
Page 413 of 528

Black plate (35,1)GMC Yukon/Yukon XL Owner Manual - 2011
Vehicle Care 10-35
Headlamp Aiming
The vehicle has a visual optical
headlamp aiming system. The aim
of the headlamps has been preset
at the factory and should need no
further adjustment.
However, if the vehicle is damaged
in a crash, the aim of the headlamps
may be affected and adjustment
may be necessary.
If oncoming vehicles flash their high
beams at you, this may mean the
vertical aim of the headlamps needs
to be adjusted.
It is recommended that the vehicle
be taken to the dealer for service if
the headlamps need to be adjusted.
It is possible, however, to re-aim the
headlamps as described.The vehicle should:.Be placed so the headlamps
are 7.6 m (25 ft) from a
light‐colored wall.
.Have all four tires on a level
surface which is level all the way
to the wall.
.Be placed so it is perpendicular
to the wall.
.Not have any snow, ice, or mud
on it.
.Be fully assembled and all other
work stopped while headlamp
aiming is being performed.
.Be loaded with a full tank of
fuel and one person or 75 kg
(160 lbs) sitting on the
driver seat.
.Have the tires properly inflated.
.Have the spare tire in its proper
location in the vehicle.Headlamp aiming is done with the
vehicle's low-beam headlamps.
The high-beam headlamps will be
correctly aimed if the low-beam
headlamps are aimed properly.
To adjust the vertical aim:
1. Open the hood. See
Hood on
page 10‑52. Locate the aim dot on the lens of the low‐beam headlamp.
3. Record the distance from the ground to the aim dot on the
low‐beam headlamp.
Page 414 of 528

Black plate (36,1)GMC Yukon/Yukon XL Owner Manual - 2011
10-36 Vehicle Care
4. At a wall, measure from theground upward (A) to the
recorded distance from
Step 3 and mark it.
5. Draw or tape a horizontal line (B) on the wall the width of the
vehicle at the height of the mark
in Step 4.
Notice: Do not cover a headlamp
to improve beam cut-off when
aiming. Covering a headlamp may
cause excessive heat build-up
which may cause damage to the
headlamp. 6. Turn on the low-beam
headlamps and place a piece
of cardboard or equivalent in
front of the headlamp not being
adjusted. This allows only the
beam of light from the headlamp
being adjusted to be seen on the
flat surface.
7. Locate the vertical headlamp
aiming screws, which are under
the hood near each headlamp
assembly.
The adjustment screw can be
turned with an E8 Torx
®socket. 8. Turn the vertical aiming screw
until the headlamp beam is
aimed to the horizontal tape
line. Turn it clockwise or
counterclockwise to raise or
lower the angle of the beam.
9. Make sure that the light from theheadlamp is positioned at the
bottom edge of the horizontal
tape line. The lamp on the
left (A) shows the correct
headlamp aim. The lamp on the
right (B) shows the incorrect
headlamp aim.
10. Repeat Steps 7 through 9 for the opposite headlamp.
Page 415 of 528
Black plate (37,1)GMC Yukon/Yukon XL Owner Manual - 2011
Vehicle Care 10-37
Bulb Replacement
For the proper type of replacement
bulbs, seeReplacement Bulbs on
page 10‑39.
For any bulb‐changing procedure
not listed in this section, contact
your dealer.
Halogen Bulbs
{WARNING
Halogen 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.
Taillamps, Turn Signal,
Stoplamps, and Back-Up
Lamps
If the vehicle is a Hybrid, see the
Hybrid Supplement for the bulb
changing procedure.
A. Stoplamp/Taillamp
B. Taillamp/Turn Signal Lamp
C. Back-up Lamp To replace one of these bulbs:
1. Open the liftgate. See
Liftgate
(Manual) on page 2‑10 or
Liftgate (Power) on page 2‑11.
2. Remove the two screws from the taillamp assembly.
3. Pull the taillamp assembly rearward until you disengage
the inner pins on the taillamp
assembly from the vehicle.
Page 416 of 528
Black plate (38,1)GMC Yukon/Yukon XL Owner Manual - 2011
10-38 Vehicle Care
4. Press the release tab, if bulbsocket has one, and turn the
bulb socket counterclockwise
to remove it from the taillamp
assembly.
5. Pull the old bulb straight out from the bulb socket.
6. Press a new bulb into the bulb socket.
7. Reinstall the socket into the taillamp assembly by turning the
bulb socket clockwise.
8. Reinstall the taillamp assembly making sure to line up the pins
with the vehicle and tighten the
screws.License Plate Lamp
1. Remove the two screws holdingeach of the license plate lamps
to the molding that is part of the
liftgate. 2. Twist and pull the license plate
lamp assembly forward through
the molding opening.
3. Remove the bulb socket from the lamp assembly by turning it
counterclockwise.
4. Pull the bulb straight out of the socket and install the new bulb.
5. Reverse Steps 1 through 3 to reinstall the license plate lamp.