2008 GMC YUKON DENALI Owners Manual

What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. SeeRecommended Fluids
and Lubricants on page 6-12.
Front Axle
When to Check and Change Lubricant
It is not necessary to regularly check front axle uid
unless you suspect there is a leak or you hear an
unusual noise. A uid 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.A:Fill Plug
B:Drain Plug
When the differential is cold, add enough lubricant
to raise the level from 0 (0 mm) to 1/8 inch
(3.2 mm) below the ller plug hole.
When the differential is at operating temperature
(warm), add enough lubricant to raise the level to
the bottom of the ller plug hole.
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. SeeRecommended Fluids
and Lubricants on page 6-12. 1500 Series
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Headlamp Aiming
The vehicle has a visual optical headlamp aiming
system. The aim of the headlamps have 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 ash their high beams at you, this
may mean the vertical aim of your headlamps needs
to be adjusted.
It is recommended that the vehicle is taken to your
dealer/retailer 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 25 ft. (7.6 m) 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.
Normally loaded with a full tank of fuel and one
person or 160 lbs (75 kg) sitting on the driver seat.
Have the tires properly inated.
Have the spare tire is 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. SeeHood Release on page 5-10
for more information.
2. 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.
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4. At a wall, measure from the ground 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 at surface.7. Locate the vertical headlamp aiming screws, which
are under the hood near each headlamp assembly.
The adjustment screw can be turned with a
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.
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9. Make sure that the light from the headlamp 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.
Bulb Replacement
For the proper type of replacement bulbs, see
Replacement Bulbs on page 5-52.
For any bulb changing procedure not listed in this
section, contact your dealer/retailer.
Halogen Bulbs
{CAUTION:
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.
5-50

Taillamps, Turn Signal, Stoplamps
and Back-up Lamps
A. Stoplamp/Taillamp
B. Turn Signal/Taillamp
C. Back-up LampTo replace one of these bulbs:
1. Remove the two
screws from the
taillamp assembly.
2. Remove the taillamp assembly.
3. Press the release tab, if equipped, and turn the
socket counterclockwise to remove it from the
taillamp assembly.
4. Pull the old bulb straight out from the socket.
5. Press a new bulb into the socket, insert the socket
into the taillamp assembly and turn the socket
clockwise into the taillamp assembly until it clicks.
6. Reinstall the taillamp assembly.
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License Plate Lamp
1. Remove the two screws holding each of the license
plate lamps to the molding that is part of the liftgate.
2. Twist and pull the license plate lamp forward
through the molding opening.3. Turn the bulb socket counterclockwise and pull the
bulb straight out of the socket.
4. Install the new bulb.
5. Reverse Steps 1 through 3 to reinstall the license
plate lamp.
Replacement Bulbs
Exterior Lamp Bulb Number
Back-up Lamp 7441
License Plate Lamp 168
Rear Turn Signal Lamp, Taillamp,
and Stoplamp3057KX
For replacement bulbs not listed here, contact your
dealer/retailer.
5-52

Windshield Wiper Blade
Replacement
Windshield wiper blades should be inspected for wear
or cracking. SeeScheduled Maintenance on page 6-4.
Replacement blades come in different types and
are removed in different ways. To replace the wiper
blade assembly:
1. Pull the windshield wiper arm connector away from
the windshield.
2. Squeeze the grooved areas on each side of the
blade, and turn the blade assembly away from
the arm connector.3. Install the new blade onto the arm connector and
make sure the grooved areas are fully set in the
locked position.
For the proper type and size, seeMaintenance
Replacement Parts on page 6-14.
5-53

Backglass Wiper Blade Replacement
1. Lift the wiper blade assembly up and out of the park
rest position.
2. Pull the wiper blade assembly away 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 assembly to the park rest
position.
5-54