2008 GMC SIERRA lock

3. Check both sides of the dipstick, and read the lower
level. The uid level must be in the COLD area,
below the cross-hatched area, for a cold check or in
the HOT or cross-hatched area for a hot check.
Be sure to keep the dipstick pointed down to get an
accurate reading.
4. If the uid level is in the acceptable range, push the
dipstick back in all the way; then ip the handle
down to lock the dipstick in place.
Consistency of Readings
Always check the uid level at least twice using the
procedure described previously. Consistency
(repeatable readings) is important to maintaining proper
uid level. If readings are still inconsistent, contact your
dealer/retailer.
How to Add Automatic Transmission
Fluid
Refer to the Maintenance Schedule to determine what
kind of transmission uid to use. SeeRecommended
Fluids and Lubricants on page 6-15.
Using a funnel, add uid down the transmission dipstick
tube only after checking the transmission uid while it
is hot. A cold check is used only as a reference. If the
uid level is low, add only enough of the proper uid to
bring the level up to the HOT area for a hot check. It does
not take much uid, generally less than one pint (0.5 L).
Do not overll.
Notice:Use of the incorrect automatic transmission
uid may damage your vehicle, and the damages
may not be covered by your warranty. Always
use the automatic transmission uid listed in
Recommended Fluids and Lubricants on page 6-15.
After adding uid, recheck the uid level as
described under “How to Check Automatic
Transmission Fluid,” earlier in this section.
When the correct uid level is obtained, push the
dipstick back in all the way; then ip the handle
down to lock the dipstick in place.
5-27

Notice:In cold weather, water can freeze and crack
the engine, radiator, heater core and other parts.
Use the recommended coolant and the proper
coolant mixture.
{CAUTION:
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol
and it will burn if the engine parts are hot
enough. Do not spill coolant on a hot engine.1. Remove the coolant
surge tank pressure
cap when the cooling
system, including the
coolant surge tank
pressure cap and upper
radiator hose, is no
longer hot.
Turn the pressure cap slowly counterclockwise
about one full turn. If you hear a hiss, wait for that to
stop. A hiss means there is still some pressure left.
2. Then keep turning the pressure cap slowly, and
remove it.
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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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Headlamps
To replace one of these bulbs:
1. Open the hood. SeeHood Release on page 5-13
for more information.
2. If you are replacing the bulb on the passenger side
remove the Engine Air Cleaner cover. SeeEngine
Air Cleaner/Filter (Gasoline Engines) on page 5-19
for more information.
3. Reach in and access the bulb sockets from inside
the engine compartment.
4. Turn the bulb socket counterclockwise to remove it
from the headlamp assembly and pull it straight out.
5. Unplug the electrical connector from the old bulb by
releasing the clips on the bulb socket.
6. Replace it with a new bulb socket.
7. Plug in the electrical connector to the new
bulb socket.
8. Reinstall the new bulb socket into the headlamp
assembly and turn it clockwise to secure.
9. Close the hood.
5-60

Center High-Mounted Stoplamp
(CHMSL) and Cargo Lamp
To replace one of these bulbs:
1. Remove the screws and lift off the lamp assembly.A. Cargo Lamp
B. Center High-Mounted Stoplamp Bulb (CHMSL)
2. Remove the CHMSL and Cargo bulbs by turning
socket counterclockwise and pulling the bulb
straight out.
3. Install the CHMSL and Cargo bulbs by pushing the
bulb straight in and turning clockwise.
4. Reinstall the lamp assembly and tighten the screws.
5-61

A. Stoplamp/Taillamp/Turn Signal Lamp
B. Back-up Lamp
C. Stoplamp/Taillamp/Turn Signal Lamp
4. Press the tab, if the vehicle has one, and turn the
bulb socket counterclockwise to remove it from the
taillamp assembly.A. Stoplamp/Taillamp/Turn
Signal Lamp
B. Stoplamp/Taillamp/Turn
Signal LampC. Back-up Lamp
D. Sidemarker Lamp
5. Pull the old bulb straight out from the socket.
6. Press a new bulb into the socket and turn the socket
clockwise into the taillamp assembly.
7. Reinstall the taillamp assembly. Dually Models
All Other Models
5-63

Taillamps (Chassis Cab Models)
A. Backup Lamp
B. Stoplamp/Taillamp/Turn Signal Lamp
To replace one of these bulbs:
1. Remove the four screws.
2. Lift the lens off the lamp assembly.
3. Turn the old bulb counterclockwise and pull the it
straight out from the socket.
4. Install a new bulb into the socket, turn it clockwise,
and press it in until it is tight.
5. Reinstall the lens and the four screws.
License Plate Lamp
To replace one of these bulbs:
1. Reach under the rear bumper for the bulb socket.
2. Turn the bulb socket counterclockwise and pull the
bulb socket out of the connector.
3. Pull the old bulb from the bulb socket, keeping the
bulb straight as you pull it out.
4. Install the new bulb.
5. Reverse Steps 1 through 3 to reinstall the
bulb socket.
5-64

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 6-17.
Tires
Your new vehicle comes with high-quality tires
made by a leading tire manufacturer. If you ever
have questions about your tire warranty and where
to obtain service, see your vehicle Warranty
booklet for details.
{CAUTION:
Poorly maintained and improperly used
tires are dangerous.
Overloading your vehicle’s tires can
cause overheating as a result of too
much exing. You could have an
air-out and a serious accident. See
Loading Your Vehicle on page 4-36.
Underinated tires pose the same
danger as overloaded tires. The
resulting accident could cause serious
injury. Check all tires frequently to
maintain the recommended pressure.
Tire pressure should be checked when
your vehicle’s tires are cold. See
Inflation - Tire Pressure on page 5-74.
Overinated tires are more likely to be
cut, punctured, or broken by a sudden
impact — such as when you hit a
pothole. Keep tires at the
recommended pressure.
Worn, old tires can cause accidents. If
the tire’s tread is badly worn, or if
your vehicle’s tires have been
damaged, replace them.
5-66