2006 GMC SIERRA four wheel drive

Four-Wheel-Drive Vehicles
Use the following procedure to tow your vehicle from
the rear:
1. Drive the vehicle onto the dolly.
2. Firmly set the parking brake. SeeParking Brake on
page 2-52
3. Put an automatic transmission in PARK (P) or a
manual transmission in FIRST (1).
4. Follow the dolly manufacturer’s instructions to
attach and secure the vehicle being towed to
the dolly and then the loaded dolly to the tow
vehicle.
For manual transmission vehicles, make sure the
wheels are straight before proceeding to the next
steps. On automatic transmission vehicles, use an
adequate clamping device to ensure that the front
wheels are locked into the straight position.{CAUTION:
Shifting a four-wheel-drive vehicle’s transfer
case into NEUTRAL can cause your vehicle to
roll even if the transmission is in PARK (P) for
an automatic transmission, or if your vehicle
is in gear, for a manual transmission. You or
others could be injured. Make sure the parking
brake is rmly set before you shift the transfer
case to NEUTRAL.
5. Shift the transfer case to NEUTRAL.
SeeFour-Wheel Drive on page 2-38
6. Release the parking brake only after the vehicle
being towed is rmly attached to the tow vehicle.
7. Turn the ignition to LOCK.
4-66

Parking on Hills
{CAUTION:
You really should not park your vehicle, with
a trailer attached, on a hill. If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But if you ever have to park your rig on a hill, here’s
how to do it:
1. Apply your regular brakes, but don’t shift into
PARK (P) yet for an automatic transmission,
or into gear for a manual transmission.
2. Have someone place chocks under the trailer
wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your
parking brake and shift into PARK (P) for an
automatic transmission, or REVERSE (R) for
a manual transmission.
5. If you have a four-wheel-drive vehicle, be sure the
transfer case is in a drive gear and not in NEUTRAL.
6. Release the regular brakes.
{CAUTION:
It can be dangerous to get out of your vehicle if
the shift lever is not fully in PARK (P) with the
parking brake rmly set. Your vehicle can roll.
If you have left the engine running, the vehicle
can move suddenly. You or others could be
injured. To be sure your vehicle will not move,
even when you are on fairly level ground, use
the steps that follow.
Always put the shift lever fully in PARK (P) with
the parking brake rmly set.
If the transfer case on four-wheel-drive vehicles
is in NEUTRAL, your vehicle will be free to roll,
even if your shift lever is in PARK (P). So, be
sure the transfer case is in a drive gear — not
in NEUTRAL.
4-91

Service............................................................5-4
Accessories and Modications..........................5-4
California Proposition 65 Warning.....................5-4
Doing Your Own Service Work.........................5-5
Adding Equipment to the Outside of
Your Vehicle..............................................5-5
Fuel................................................................5-5
Gasoline Octane............................................5-6
Gasoline Specications....................................5-6
California Fuel...............................................5-7
Additives.......................................................5-7
Fuel E85 (85% Ethanol)..................................5-8
Fuels in Foreign Countries...............................5-9
Filling the Tank............................................5-10
Filling a Portable Fuel Container.....................5-11
Checking Things Under the Hood....................5-12
Hood Release..............................................5-13
Engine Compartment Overview.......................5-14
Engine Oil (Gasoline Engine)..........................5-20
Engine Oil Life System (Gasoline Engine)........5-23
Engine Air Cleaner/Filter (Gasoline Engines).......5-25
Automatic Transmission Fluid
(Except Allison Transmission
®) ....................5-28Automatic Transmission Fluid
(Allison Transmission
®) ...............................5-30
Manual Transmission Fluid.............................5-33
Hydraulic Clutch...........................................5-34
Engine Coolant.............................................5-35
Coolant Surge Tank Pressure Cap..................5-37
Engine Overheating.......................................5-37
Overheated Engine Protection Operating Mode
(V8 Engines Only)......................................5-39
Cooling System............................................5-40
Engine Fan Noise.........................................5-45
Power Steering Fluid.....................................5-45
Windshield Washer Fluid................................5-46
Brakes........................................................5-47
Battery........................................................5-51
Jump Starting...............................................5-52
Rear Axle.......................................................5-58
Four-Wheel Drive............................................5-59
Front Axle......................................................5-60
Noise Control System.....................................5-62
Tampering with Noise Control System
Prohibited.................................................5-62
Section 5 Service and Appearance Care
5-1

Notice:Ignoring these steps could result in costly
damage to your vehicle that would not be covered
by your warranty.
Trying to start your vehicle by pushing or pulling it
will not work, and it could damage your vehicle.
1. Check the other vehicle. It must have a 12-volt
battery with a negative ground system.
Notice:If the other vehicle’s system is not a 12-volt
system with a negative ground, both vehicles can
be damaged. Only use vehicles with 12-volt systems
with negative grounds to jump start your vehicle.
2. If you have a vehicle with a diesel engine with two
batteries (or more), you should know before you
begin that, especially in cold weather, you may not
be able to get enough power from a single battery in
another vehicle to start your diesel engine.
If your vehicle has more than one battery, use the
battery that is closer to the starter — this will reduce
electrical resistance.3. Get the vehicles close enough so the jumper cables
can reach, but be sure the vehicles are not touching
each other. If they are, it could cause a ground
connection you do not want. You would not be able
to start your vehicle, and the bad grounding
could damage the electrical systems.
To avoid the possibility of the vehicles rolling, set
the parking brake rmly on both vehicles involved in
the jump start procedure. Put an automatic
transmission in PARK (P) or a manual transmission
in NEUTRAL before setting the parking brake.
If you have a four-wheel-drive vehicle, be sure the
transfer case
is in a drive gear, not in NEUTRAL.
Notice:If you leave your radio or other accessories
on during the jump starting procedure, they could
be damaged. The repairs would not be covered
by your warranty. Always turn off your radio and
other accessories when jump starting your vehicle.
4. Turn off the ignition on both vehicles. Unplug
unnecessary accessories plugged into the cigarette
lighter or accessory power outlets. Turn off the radio
and all lamps that are not needed. This will avoid
sparks and help save both batteries. And it could
save the radio!
5-53

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

Changing a Flat Tire
If a tire goes at, avoid further tire and wheel damage
by driving slowly to a level place. Turn on your
hazard warning ashers. SeeHazard Warning Flashers
on page 3-6for more information.
{CAUTION:
Changing a tire can be dangerous. The vehicle
can slip off the jack and roll over or fall on you
or other people. You and they could be badly
injured or even killed. Find a level place to
change your tire. To help prevent the vehicle
from moving:
1. Set the parking brake rmly.
2. Put an automatic transmission shift lever
in PARK (P), or shift a manual transmission
to FIRST (1) or REVERSE (R).
3. If you have a four-wheel-drive vehicle,
be sure the transfer case is in a drive
gear – not in NEUTRAL.
4. Turn off the engine and do not restart while
the vehicle is raised.
5. Do not allow passengers to remain in the
vehicle.
CAUTION: (Continued)
CAUTION: (Continued)
To be even more certain the vehicle will not
move, put blocks at the front and rear of the
tire farthest away from the one being changed.
That would be the tire on the other side, at the
opposite end of the vehicle.
When your vehicle has a at tire, use the following
example as a guide to assist you in the placement of
the wheel blocks.
The following information will tell you next how to use
the jack and change a tire.
5-91

Spare Tire
Your vehicle, when new, had a fully-inated spare tire.
A spare tire may lose air over time, so check its
ination pressure regularly. SeeInation - Tire Pressure
on page 5-79andLoading Your Vehicle on page 4-48
for information regarding proper tire ination and loading
your vehicle. For instruction on how to remove, install
or store a spare tire, seeRemoving the Flat Tire
and Installing the Spare Tire on page 5-96andStoring
a Flat or Spare Tire and Tools on page 5-108.
Your vehicle may have a different size spare tire than
the road tires originally installed on your vehicle.
This spare tire was developed for use on your vehicle,
so it is all right to drive on it. If your vehicle has
four-wheel drive and the different size spare tire is
installed, keep the vehicle in two-wheel drive.Notice:If your vehicle has four-wheel drive and the
different size spare tire is installed on your vehicle,
do not drive in four-wheel drive until you can have
your at tire repaired and/or replaced. You could
damage your vehicle, and the repair costs would not
be covered by your warranty. Never use four-wheel
drive when the different size spare tire is installed
on your vehicle.
After installing the spare tire on your vehicle, you should
stop as soon as possible and make sure the spare
tire is correctly inated. Have the damaged or at road
tire repaired or replaced as soon as you can and
installed back onto your vehicle. This way, the spare tire
will be available in case you need it again.
Do not mix tires and wheels of different sizes, because
they will not t. Keep your spare tire and its wheel
together. If your vehicle has a spare tire that does not
match your vehicle’s original road tires and wheels
in size and type, do not include the spare in the
tire rotation.
5-112

Fuses Usage
IGN 3 Ignition, Heated Seats
4WDFour-Wheel Drive System,
Auxiliary Battery
HTR A/C Climate Control System
LOCK (Relay)Power Door Lock Relay
(Lock Function)
HVAC 1 Climate Control System
LT DRDriver’s Door Harness
Connection
CRUISECruise Control, Power Take
Off (PTO)
UNLCK (Relay)Power Door Lock Relay
(Unlock Function)
RR FOG LP Not Used
BRAKE Anti-Lock Brake SystemFuses Usage
DRIVER UNLCKPower Door Lock Relay
(Driver’s Door Unlock
Function)
IGN 0 TCM
TBC IGN 0 Truck Body Controller
VEH CHMSLVehicle and Trailer High
Mounted Stoplamp
LT TRLR ST/TRN Left Turn Signal/Stop Trailer
LT TRNLeft Turn Signals and
Sidemarkers
VEH STOPVehicle Stoplamps, Brake
Module, Electronic Throttle
Control Module
RT TRLR ST/TRN Right Turn Signal/Stop Trailer
RT TRNRight Turn Signals and
Sidemarkers
5-125