2003 GMC SONOMA Owner's Manual

Rear Axle
When to Check and Change Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant and when to change it. See
Part A: Scheduled Maintenance Services on page 6-4.
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 thefiller plug hole,
you’ll need to add some lubricant. Add enough lubricant
to raise the level to the bottom of thefiller plug hole.
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. SeePart D: Recommended
Fluids and Lubricants on page 6-33.
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Four-Wheel Drive
Lubricant checks in this section also apply to these
vehicles. However, there are two additonal systems that
need lubrication.
Transfer Case
When to Check Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant. SeePart C: Periodic
Maintenance Inspections on page 6-31.
How to Check Lubricant
To get and accurate reading, the vehicle should be on
a level service.
If the level is below the bottom of thefiller plug hole, you’ll
need to add some lubricant. Remove the plug and add
enough lubricant to raise the level to the bottom of the
filler plug hole. Use care not to overtighten the plug.
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. SeePart D: Recommended
Fluids and Lubricants on page 6-33.
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Front Axle
When to Check and Change Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant and when to change it. See
Part A: Scheduled Maintenance Services on page 6-4.
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 thefiller plug hole,
you may need to add some lubricant.
When the differential is cold, add enough lubricant to
raise the level to 1/2 inch (12 mm) below thefiller
plug hole.
When the differential is at operating temperature
(warm), add enough lubricant to raise the level to the
bottom of thefiller plug hole.
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. SeePart D: Recommended
Fluids and Lubricants on page 6-33.
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Bulb Replacement
SeeReplacement Bulbs on page 5-55for the proper
types of bulbs to use. For any bulb changing procedure
not listed in this section, contact your GM dealer’s
service department.
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.
Headlamps
One-Piece Composite Headlamp
System
1. Open the hood.
2. Remove the black retainer clips by lifting up.
3. Pull the headlamp assembly out.
4. Unplug the electrical connector.
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5. Turn the bulb assembly counterclockwise to
remove it from the headlamp assembly.
6. Put the new bulb into the bulb assembly and
reinstall it in the headlamp assembly by turning
it clockwise until it is tight.
7. Plug in the electrical connector.
8. Put the headlamp assembly back into the vehicle.
9. Install the two retaining clips.
10. Close the hood.
Two-Piece Composite Headlamp
System
1. Open the hood.
2. Remove the black retainer clips by lifting up.
3. Unplug the electrical connector.
4. Pull the headlamp lens assembly out.
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5. Turn the bulb assembly counterclockwise to remove
it from the headlamp assembly.
6. Put the new bulb into the bulb assembly and
reinstall it in the headlamp assembly by turning
it clockwise until it is tight.
7. Plug in the electrical connector.
8. Put the headlamp lens assembly back into the
vehicle.
9. Install the two retaining clips.
10. Close the hood.
One-Piece Front Turn Signal Lamps
1. Remove the headlamp assembly as shown in
″One-Piece Composite Headlamp System″
underHeadlamps on page 5-50.
2. Twist the bulb socket
counterclockwise
to remove it from the
headlamp assembly.
3. Pull the bulb straight out to remove it from the
socket.
4. Push the new bulb into the socket until it snaps
into place.
5. Put the bulb socket into the lamp assembly and
twist it clockwise until it is tight.
6. Put the headlamp assembly back into the vehicle.
7. Install the two retaining clips.
8. Close the hood.
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Two-Piece Front Turn Signal Lamps
1. Remove the headlamp assembly as shown in
″Two-Piece Composite Headlamp System″
underHeadlamps on page 5-50.
2. Locate the locking
tabs on the assembly.
Squeeze the tabs
together and push that
end of the assembly
out while holding
the tabs. The assembly
will swing out.3. Unplug the electrical connector.
4. Turn the harness bulb socket counterclockwise to
remove it. Pull the bulb straight out to remove it
from the socket.
5. Push the new bulb into the socket until it snaps
into place.
6. Put the socket into the lamp assembly and turn it
clockwise until it is tight.
7. To reinstall the assembly, snap the outboard end of
the lamp assembly back into the vehicle. Then
swing the assembly in and snap it into place.
8. Install the two retaining clips.
9. Close the hood.
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Center High-Mounted Stoplamp
(CHMSL)
1. Remove the lens retaining screws.
2. Remove the lens.3. Remove the bulb.
4. Install a new bulb.
5. Reinstall the lens and tighten the screws.
If equipment such as a cap or camper is installed on
your vehicle, a center high-mounted stoplamp feed wire
is provided along the driver’s side rear frame. This
wire should be used to install a center high-mounted
stoplamp in the cap or camper.
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