GMC SIERRA 2006 Owner's Manual

The proper level for the 2500HD with the 6.6L diesel
engine (RPO LLY) or 8.1L V8 engine (RPO L18), and
3500 Series is from 0.6 to 0.8 inch (17 mm to 21 mm)
below the bottom of the ller plug hole.
Add only enough uid to reach the proper level.
What to Use
To determine what kind of lubricant to use see
Recommended Fluids and Lubricants (Gasoline Engine)
on page 6-14.
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
Manual Transfer Case
5-59

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 transfer case, 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.
When to Change Lubricant
Refer to the Maintenance Schedule to determine how
often to change the lubricant. SeeScheduled
Maintenance (Gasoline Engine) on page 6-4.
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. SeeRecommended Fluids
and Lubricants (Gasoline Engine) on page 6-14.
Front Axle
When to Check 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. Automatic Transfer Case
5-60

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 to 0 to 3/8 inch (9.5 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
To determine what kind of lubricant to use see
Recommended Fluids and Lubricants (Gasoline Engine)
on page 6-14.
5-61

Noise Control System
Tampering with Noise Control
System Prohibited
The following information relates to compliance with
federal noise emission standards for vehicles with a
Gross Vehicle Weight Rating (GVWR) of more than
10,000 lbs (4 536 kg). The Maintenance Schedule
provides information on maintaining the noise control
system to minimize degradation of the noise emission
control system during the life of your vehicle. The noise
control system warranty is given in your warranty booklet.
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 purpose
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 equipped) inoperative so as to allow engine
speed to exceed manufacturer specications.
Fan and Drive:

Removal of fan clutch (if equipped) or rendering
clutch inoperative.
Removal of the fan shroud (if equipped).
Air Intake:

Removal of the air cleaner silencer.
Modication of the air cleaner.
Exhaust:

Removal of the muffler and/or resonator.
Removal of the exhaust pipes and exhaust pipe
clamps.
5-62

Bulb Replacement
For the proper type of replacement bulbs, see
Replacement Bulbs on page 5-70.
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.
Headlamps
To replace a headlamp bulb, do the following:
1. Open the hood. SeeHood Release on page 5-13
for more information.
2. Remove the two pins on the top of the headlamp
assembly. To remove the pins, turn the outer pin
outward and pull it straight up. To remove the
inner pin, turn it in and pull it straight up.
5-63

A. Low-Beam Headlamp
B. High-Beam Headlamp
3. Pull the headlamp assembly out.
4. Unplug the electrical connector.
5. Turn the old bulb counterclockwise and remove it
from the headlamp assembly.
6. Install the new bulb into the assembly and turn it
clockwise until it is tight.
7. Plug in the electrical connector.
8. Reinstall the headlamp assembly.
9. Reinstall and tighten the two pins.
Front Turn Signal, Sidemarker and
Daytime Running Lamps
A. Sidemarker Lamp
B. Retainer Clip
C. Front Turn Signal Lamp
D. Daytime Running Lamp (DRL)
5-64

To replace a front turn signal, sidemarker or DRL bulb,
do the following:
1. Open the hood. SeeHood Release on page 5-13
for more information.
2. Remove the headlamp assembly as described
previously. SeeHeadlamps on page 5-63for
more information.
3. Press the retainer clip (B), located behind the turn
signal assembly, towards the outside of the vehicle.4. Pull the turn signal assembly out of the vehicle.
5. Press the locking release lever, turn the bulb socket
counterclockwise and remove it from the turn signal
assembly.
6. Remove the old bulb from the bulb socket.
7. Install a new bulb into the bulb socket.
8. Insert the bulb socket into the turn signal assembly
and turn it clockwise until it locks.
9. Reinstall the turn signal assembly back into the
vehicle placing the hook and posts on the inner side
into the alignment holes rst, then the outer side into
the retainer bracket until you hear a click.
10. Reinstall the headlamp assembly.
5-65

Roof Marker Lamps
To replace a roof marker lamp bulb, do the following:
1. Remove the
two screws and
lift off the lens.
2. Install a new bulb into
the socket and turn
clockwise until it locks
into place.
3. Reinstall the lens and tighten the screws.To replace a center roof marker lamp bulb, do the
following:
1. Remove the six screws from the center roof marker
lamp assembly.
2. Turn the old bulb counterclockwise to remove it
from the socket.
3. Reinstall the lens and tighten the screws.
5-66

Center High-Mounted
Stoplamp (CHMSL) and
Cargo Lamp
To replace one of these bulbs, do the following:
1. Remove the screws and lift off the lamp assembly.A. Cargo Lamp
B. Center High-Mounted Stoplamp Bulb
2. Remove the back plate from the assembly by
pressing the release tabs.
3. Remove the CHMSL bulb by pulling the bulb
straight out from the holder back plate.
Remove a cargo bulb by turning the socket
counterclockwise and pulling the bulb straight out.
5-67

4. If a CHMSL bulb is replaced, put the new bulb into
the socket and press it in until it is tight.
If a cargo lamp is replaced, put a new cargo lamp
bulb into the socket and press it in until it is tight
before turning the socket counterclockwise.
5. Reinstall the back plate into the lamp assembly.
6. Reinstall the lamp assembly and tighten the screws.
Pickup Box Identication and
Fender Marker Lamps
To replace a pickup box identication or fender marker
lamp bulb, do the following:
1. Remove the screws and lamp assembly.
2. Unplug the lamp assembly harness.
3. Gently pry the individual lamp from the lamp
assembly.
4. Unplug the lamp.
5. Plug in a new lamp and snap it into the assembly.
6. Reinstall the lamp assembly.
Taillamps, Turn Signal, Stoplamps
and Back-up Lamps
To replace one of these bulbs, do the following:
1. Open the tailgate.Tailgate on page 2-14for more
information.
2. Remove the two rear
lamp assembly screws
near the tailgate
latch and pull out the
lamp assembly.
5-68