2007 GMC YUKON XL Owners Manual

Four-Wheel Drive
Lubricant checks in this section also apply to these
vehicles. There are two additional systems that
need lubrication.
Transfer Case
When to Check Lubricant
It is not necessary to regularly check transfer case
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.
If the level is below the bottom of the ller plug
hole, you’ll need to add some lubricant. Add
enough lubricant to raise the level to the bottom of
the ller plug hole. Use care not to overtighten
the plug.
Automatic Transfer Case
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When to Change Lubricant
Refer to the Maintenance Schedule to determine
how often to change the lubricant. See
Scheduled Maintenance on page 555.
What to Use
Refer to the Maintenance Schedule to determine
what kind of lubricant to use. SeeRecommended
Fluids and Lubricants on page 564.
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.
If the level is below the bottom of the ller plug
hole, located on the front axle, you may need
to add some lubricant:
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.
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What to Use
Refer to the Maintenance Schedule to determine
what kind of lubricant to use. SeeRecommended
Fluids and Lubricants on page 564.
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 an accident,
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 for service if the headlamps need to be
adjusted. It is possible however, to re-aim
the headlamps as described in the following
procedure.The vehicle should be properly prepared as
follows:
The vehicle should be placed so the
headlamps are 25 ft. (7.6 m) from a light
colored wall.
The vehicle must have all four tires on a level
surface which is level all the way to the wall.
The vehicle should be placed so it is
perpendicular to the wall.
The vehicle should not have any snow, ice, or
mud on it.
The vehicle should be fully assembled and all
other work stopped while headlamp aiming is
being performed.
The vehicle should be normally loaded with
a full tank of fuel and one person or
160 lbs (75 kg) sitting on the driver’s seat.
Tires should be properly inated.
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.
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To adjust the vertical aim, do the following:
1. Open the hood. SeeHood Release on
page 435for more information.
2. Locate the aim dot on the lens of the
low-beam headlamp.
3. Measure the distance from the ground to the
aim dot on the low-beam headlamp. Record
the distance.4. At the wall or other at surface, 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
or at surface 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.
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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.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.
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Bulb Replacement
For the proper type of replacement bulbs, see
Replacement Bulbs on page 481.
For any bulb changing procedure not listed in this
section, contact your dealer.
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.
Taillamps, Turn Signal, Stoplamps
and Back-up Lamps
A. Taillamp/Turn Signal
Lamp
B. Back-up Lamp
C. Stoplamp/Taillamp
To replace one of these bulbs, do the following:
1. Open the liftgate. SeePower Liftgate on
page 125for more information.
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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.
4. Press the release tab, if bulb socket 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 and
insert it into the taillamp assembly. Turn the
bulb socket clockwise into the taillamp
assembly until it clicks.
7. Reinstall the taillamp assembly. When
reinstalling, make sure to line up the pins on
the taillamp assembly with the vehicle.
If you do not do this, you will not be able
correctly install 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 steps1–3toreinstall the license
plate lamp.
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