
Black plate (14,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-14 Vehicle Care
Automatic Transmission
Fluid (6-Speed
Transmission)
When to Check and Change
Automatic Transmission Fluid
It is usually not necessary to check
the transmission fluid level. The
only reason for fluid loss is a
transmission leak or overheated
transmission. If a small leak is
suspected, then use the following
checking procedures to check the
fluid level. However, if there is a
large leak, then it may be necessary
to have the vehicle towed to a
dealer service department and have
it repaired before driving the vehicle
further.
Notice:Use of the incorrect
automatic transmission fluid
may damage the vehicle, and the
damages may not be covered by
the vehicle warranty. Always use
the automatic transmission fluid
listed in Recommended Fluids
and Lubricants on page 11‑12. Change the fluid and filter at the
scheduled maintenance intervals
listed in
Maintenance Schedule on
page 11‑3. Be sure to use the
transmission fluid listed in
Recommended Fluids and
Lubricants on page 11‑12.How to Check Automatic
Transmission Fluid
Notice: Too much or too
little fluid can damage the
transmission. Too much can
mean that some of the fluid could
come out and fall on hot engine
parts or exhaust system parts,
starting a fire. Too little fluid
could cause the transmission
to overheat. Be sure to get an
accurate reading if checking the
transmission fluid. Before checking the fluid level,
prepare the vehicle as follows:
1. Start the engine and park the
vehicle on a level surface. Keep
the engine running.
2. Apply the parking brake and place the shift lever in P (Park).
3. With your foot on the brake pedal, move the shift lever
through each gear range,
pausing for about three seconds
in each range. Then, move the
shift lever back to P (Park).
4. Allow the engine to idle (500 –800 rpm) for at least
1 minute. Slowly release the
brake pedal.
5. Keep the engine running and press the Trip/Fuel button or
trip odometer reset stem until
TRANS TEMP (Transmission
Temperature) displays on the
Driver Information Center (DIC).

Black plate (15,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-15
6. Using the TRANS TEMPreading, determine and
perform the appropriate check
procedure. If the TRANS TEMP
reading is not within the required
temperature ranges, allow the
vehicle to cool, or operate the
vehicle until the appropriate
transmission fluid temperature is
reached.
Cold Check Procedure
Use this procedure only as a
reference to determine if the
transmission has enough fluid to be
operated safely until a hot check
procedure can be made. The hot
check procedure is the most
accurate method to check the
fluid level. Perform the hot check
procedure at the first opportunity.
Use this cold check procedure
to check fluid level when the
transmission temperature is
between 27°C and 32°C
(80°F and 90°F).
1. Locate the transmission dipstick at the rear of the engine
compartment, on the passenger
side of the vehicle.
See Engine Compartment
Overview on page 10‑6 for more
information.
2. Flip the handle up, then pull out the dipstick and wipe it with a
clean rag or paper towel.
3. Install the dipstick by pushing it back in all the way; wait
three seconds, and then pull it
back out again.
4. Check both sides of the dipstick and read the lower level. Repeat
the check procedure to verify the
reading.5. If the fluid level is below theCOLD check band, add only
enough fluid as necessary to
bring the level into the COLD
band. It does not take much
fluid, generally less than 0.5 Liter
(1 Pint). Do not overfill.
6. Perform a hot check at the first opportunity after the
transmission reaches a normal
operating temperature between
71°C to 93°C (160°F to 200°F).
7. If the fluid level is in the acceptable range, push the
dipstick back in all the way,
then flip the handle down to
lock the dipstick in place.

Black plate (16,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-16 Vehicle Care
Hot Check Procedure
Use this procedure to check the
transmission fluid level when the
transmission fluid temperature
is between 71°C and 93°C
(160°F and 200°F).
The hot check is the most accurate
method to check the fluid level. The
hot check should be performed at
the first opportunity in order to verify
the cold check. The fluid level rises
as fluid temperature increases,
so it is important to ensure the
transmission temperature is within
range.
1. Locate the transmission dipstickat the rear of the engine
compartment, on the passenger
side of the vehicle. See
Engine Compartment
Overview on page 10‑6 for more
information.
2. Flip the handle up, then pull out the dipstick and wipe it with a
clean rag or paper towel.
3. Install the dipstick by pushing it back in all the way; wait
three seconds, and then pull it
back out again.
4. Check both sides of the dipstick and read the lower level. Repeat
the check procedure to verify the
reading.5. Safe operating level is within theHOT cross hatch band on the
dipstick. If the fluid level is not within the HOT band, and the
transmission temperature is
between 71°C and 93°C
(160°F and 200°F), add or drain
fluid as necessary to bring the
level into the HOT band. If the
fluid level is low, add only
enough fluid to bring the level
into the HOT band. It does not
take much fluid, generally less
than 0.5 L (1 pint). Do not
overfill.
6. If the fluid level is in the acceptable range, push the
dipstick back in all the way, then
flip the handle down to lock the
dipstick in place.
Consistency of Readings
Always check the fluid level at least
twice using the procedure described
previously. Consistency (repeatable
readings) is important to maintaining
proper fluid level. If readings are still
inconsistent, contact the dealer.

Black plate (25,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-25
loading, trailer towing, and/or high
outside temperatures, the fan speed
increases as the clutch more fully
engages, so an increase in fan
noise may be heard. This is normal
and should not be mistaken as the
transmission slipping or making
extra shifts. It is merely the cooling
system functioning properly. The fan
will slow down when additional
cooling is not required and the
clutch disengages.
This fan noise may also be heard
when starting the engine. It will go
away as the fan clutch partially
disengages.
If the vehicle has electric cooling
fans, the fans may be heard
spinning at low speed during most
everyday driving. The fans may
turn off if no cooling is required.
Under heavy vehicle loading, trailer
towing, high outside temperatures,
or operation of the air conditioning
system, the fans may change to
high speed and an increase in fan
noise may be heard. This is normal
and indicates that the coolingsystem is functioning properly. The
fans will change to low speed when
additional cooling is no longer
required.
Power Steering Fluid
See
Engine Compartment Overview
on page 10‑6 for reservoir location.
When to Check Power Steering
Fluid
It is not necessary to regularly
check power steering fluid unless
there is a leak suspected in the
system or an unusual noise is
heard. A fluid loss in this system
could indicate a problem. Have the
system inspected and repaired.
How to Check Power Steering
Fluid
Notice:Extremely small amounts
of contamination can cause
steering system damage and
cause it to not work properly. Do
not allow contaminants to contact
the fluid side of the reservoir cap/
dipstick or to enter the reservoir.
To check the power steering fluid:
1. Turn the key off and let the engine compartment cool down.
2. Wipe the cap and the top of the reservoir clean.
3. Unscrew the cap and wipe the dipstick with a clean rag.
4. Replace the cap and completely tighten it.
5. Remove the cap again and look at the fluid level on the dipstick.
The level should be at the FULL
COLD mark. If necessary, add only
enough fluid to bring the level up to
the mark.

Black plate (4,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
12-4 Technical Data
ApplicationCapacities
Metric English
Transmission Fluid - Automatic (Pan Removal and Filter Replacement)
4-Speed Transmission 4L60-E Electronic Transmission 4.7 L 5.0 qt
6-Speed Transmission 6L80-E 5.7 L 6.0 qt
6-Speed Transmission 6L90-E 6.0 L 6.3 qt
6-Speed Transmission Allison 7.0 L 7.4 qt
Transmission Fluid - Manual (Drain and Refill) 1500 Series 4.4 L 4.6 qt
3500 Series 3.5 L 3.7 qt
Wheel Nut Torque 190 Y140 ft lb
All capacities are approximate. When adding, be sure to fill to the approximate level, as recommended in this
manual. Recheck fluid level after filling.

Black plate (1,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
INDEX i-1
A
Accessories andModifications . . . . . . . . . . . . . . . . . 10-3
Accessory Power . . . . . . . . . . . . . . 9-29
Active Fuel Management
®. . . . . 9-32
Add-On Electrical Equipment . . . . . . . . . . . . . . . . . . 9-105
Adding a Snow Plow or Similar Equipment . . . . . . . . . . . 9-106
Additional Information, OnStar
®. . . . . . . . . . . . . . . . . . . . . . 14-5
Adjustable Throttle and Brake Pedal . . . . . . . . . . . . . . . . . . 9-25
Adjustments Lumbar, Front Seats . . . . . . . . . . . 3-4
Air Cleaner/Filter, Engine . . . . . 10-17
Air Vents . . . . . . . . . . . . . . . . . . . . . . 8-10
Airbag System
Check . . . . . . . . . . . . . . . . . . . . . . . . 3-38
How Does an AirbagRestrain? . . . . . . . . . . . . . . . . . . . 3-27
Passenger Sensing System . . . . . . . . . . . . . . . . . . . . . . 3-32
What Makes an Airbag Inflate? . . . . . . . . . . . . . . . . . . . . . . 3-27 Airbag System (cont'd)
What Will You See after an
Airbag Inflates? . . . . . . . . . . . . . 3-27
When Should an Airbag
Inflate? . . . . . . . . . . . . . . . . . . . . . . 3-25
Where Are the Airbags? . . . . . . 3-23
Airbags Adding Equipment to theVehicle . . . . . . . . . . . . . . . . . . . . . . 3-37
Light On-Off . . . . . . . . . . . . . . . . . . 5-19
On-Off Light . . . . . . . . . . . . . . . . . . 5-19
On-Off Switch . . . . . . . . . . . . . . . . 3-29
Passenger Status Indicator . . . 5-21
Readiness Light . . . . . . . . . . . . . . 5-18
Servicing Airbag-Equipped Vehicles . . . . . . . . . . . . . . . . . . . . . 3-36
System Check . . . . . . . . . . . . . . . . 3-21
Alarm System
Anti-theft . . . . . . . . . . . . . . . . . . . . . . 2-11
AM-FM Radio . . . . . . . . . . . . . . . . . . . 7-9
Antenna Satellite Radio . . . . . . . . . . . . . . . . 7-15
Anti-theft
Alarm System . . . . . . . . . . . . . . . . 2-11
Alarm System Messages . . . . . 5-45 Antilock Brake
System (ABS) . . . . . . . . . . . . . . . . 9-53
Warning Light . . . . . . . . . . . . . . . . . 5-26
Appearance Care Exterior . . . . . . . . . . . . . . . . . . . . . 10-98
Interior . . . . . . . . . . . . . . . . . . . . . 10-101
Ashtrays . . . . . . . . . . . . . . . . . . . . . . . 5-11
Assistance Program,
Roadside . . . . . . . . . . . . . . . 13-7, 13-9
Audio Players . . . . . . . . . . . . . . . . . 7-15 CD . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-15
CD/DVD . . . . . . . . . . . . . . . . . . . . . . 7-21
Audio System Fixed Mast Antenna . . . . . . . . . . 7-15
Radio Reception . . . . . . . . . . . . . . 7-14
Rear Seat (RSA) . . . . . . . . . . . . . 7-46
Theft-Deterrent Feature . . . . . . . . 7-2
Automatic Door Locks . . . . . . . . . . . . . . . . . . . . 2-8
Headlamp System . . . . . . . . . . . . . 6-4
Transmission . . . . . . . . . . . . . . . . . 9-35
TransmissionFluid . . . . . . . . . . . . . . . 10-11, 10-14

Black plate (2,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
i-2 INDEX
Automatic TransmissionManual Mode . . . . . . . . . . . . . . . . . 9-38
Shift Lock Control
Function Check . . . . . . . . . . . 10-35
Auxiliary Devices . . . . . . . . . . . . . . . . . . . . . . . 7-32
Roof Mounted Lamp . . . . . . . . . . . 6-6
Axle, Front . . . . . . . . . . . . . . . . . . . . 10-31
Axle, Rear . . . . . . . . . . . . . . . . . . . . 10-32
B
Battery . . . . . . . . . . . . . . . . . . . . . . . 10-30 Jump Starting . . . . . . . . . . . . . . . 10-88
Load Management . . . . . . . . . . . . . 6-9
Power Protection . . . . . . . . . . . . . 6-10
Voltage and Charging
Messages . . . . . . . . . . . . . . . . . . . 5-39
Blade Replacement, Wiper . . . 10-36
Bluetooth . . . . . . . . . . . . . . . . . . . . . . 7-48
Brake
Pedal and AdjustableThrottle . . . . . . . . . . . . . . . . . . . . . . 9-25
System Warning Light . . . . . . . . 5-25 Brakes . . . . . . . . . . . . . . . . . . . . . . . . 10-27
Antilock . . . . . . . . . . . . . . . . . . . . . . . 9-53
Assist . . . . . . . . . . . . . . . . . . . . . . . . . 9-54
Fluid . . . . . . . . . . . . . . . . . . . . . . . . 10-28
Parking . . . . . . . . . . . . . . . . . . . . . . . 9-54
System Messages . . . . . . . . . . . . 5-40
Braking . . . . . . . . . . . . . . . . . . . . . . . . . 9-4
Break-In, New Vehicle . . . . . . . . . 9-25
Bulb Replacement . . . . . . . . . . . . 10-43
Center High-MountedStoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . . 10-42
Fog Lamps . . . . . . . . . . . . . . . . . . . . 6-6
Halogen Bulbs . . . . . . . . . . . . . . 10-39
Headlamp Aiming . . . . . . . . . . . 10-37
Headlamps . . . . . . . . . . . . . . . . . 10-39
Headlamps, Front Turn Signal, Sidemarker, and
Parking Lamps . . . . . . . . . . . . 10-39
License Plate Lamps . . . . . . . 10-42 Bulb Replacement (cont'd)
Pick-up Box Identification
and Fender Marker
Lamps . . . . . . . . . . . . . . . . . . . . 10-40
Taillamps . . . . . . . . . . . . . . . . . . . 10-40
Taillamps, Turn Signal, Stoplamps, and
Back-up Lamps . . . . . . . . . . . 10-41
Buying New Tires . . . . . . . . . . . . . 10-68
C
Calibration . . . . . . . . . . . . . . . . . . . . . . 5-5
California
Fuel Requirements . . . . . . . . . . . 9-69
Perchlorate MaterialsRequirements . . . . . . . . . . . . . . . 10-3
Warning . . . . . . . . . . . . . . . . . . . . . . 10-3
Camera, Rear Vision . . . . . . . . . . 9-62
Canadian Vehicle Owners . . . . . . . . iii
Capacities and Specifications . . . . . . . . . . . . . . . . 12-2

Black plate (12,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
i-12 INDEX
Service (cont'd)Parts Identification Label . . . . . 12-1
Publications Ordering
Information . . . . . . . . . . . . . . . . 13-16
Scheduling Appointments . . . 13-12
Servicing the Airbag . . . . . . . . . . . 3-36
Shift Lock Control Function Check, Automatic
Transmission . . . . . . . . . . . . . . . . 10-35
Shifting Into Park . . . . . . . . . . . . . . . . . . . . . . 9-30
Out of Park . . . . . . . . . . . . . . . . . . . 9-32
Signals, Turn and Lane-Change . . . . . . . . . . . . . . . . . 6-5
Snow Plow . . . . . . . . . . . . . . . . . . . 9-106
Specifications and Capacities . . . . . . . . . . . . . . . . . . . . 12-2
Speedometer . . . . . . . . . . . . . . . . . . 5-13
StabiliTrak
OFF Light . . . . . . . . . . . . . . . . . . . . . 5-27
System . . . . . . . . . . . . . . . . . . . . . . . 9-55
Start Assist, Hills . . . . . . . . . . . . . . 9-54
Start Vehicle, Remote . . . . . . . . . . 2-5 Starter Switch Check . . . . . . . . . 10-35
Starting the Engine . . . . . . . . . . . . 9-27
Starting the Vehicle
Messsages . . . . . . . . . . . . . . . . . . . 5-45
Steering . . . . . . . . . . . . . . . . . . . . . . . . 9-4 Fluid, Power . . . . . . . . . . . . . . . . 10-25
Wheel Adjustment . . . . . . . . . . . . . 5-2
Wheel Controls . . . . . . . . . . . . . . . . 5-2
Stoplamps and Back-up Lamps Bulb Replacement . . . . . . . . . . 10-41
Storage Areas
Center Console . . . . . . . . . . . . . . . . 4-2
Glove Box . . . . . . . . . . . . . . . . . . . . . 4-1
Instrument Panel . . . . . . . . . . . . . . 4-1
Stuck Vehicle . . . . . . . . . . . . . . . . . . 9-15
Sun Visors . . . . . . . . . . . . . . . . . . . . . 2-21
Sunroof . . . . . . . . . . . . . . . . . . 2-22, 2-23
Switches Airbag On-Off . . . . . . . . . . . . . . . . . 3-29
Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . iv
System Infotainment . . . . . . . . . . . . . . . . . . . 7-1
Noise Control . . . . . . . . . . . . . . . 10-34T
Tachometer . . . . . . . . . . . . . . . . . . . . 5-13
Tailgate . . . . . . . . . . . . . . . . . . . . . . . . 2-10
Taillamps . . . . . . . . . . . . . . . . . . . . . 10-40Bulb Replacement . . . . . . . . . . 10-41
Text Telephone (TTY) Users . . . 13-6
Theft-Deterrent Systems . . . . . . . 2-13 Immobilizer . . . . . . . . . . . . . . . . . . . 2-12
Throttle, Adjustable . . . . . . . . . . . . 9-25
Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Tires Buying New Tires . . . . . . . . . . . 10-68
Chains . . . . . . . . . . . . . . . . . . . . . . 10-74
Changing . . . . . . . . . . . . . . . . . . . 10-76
Designations . . . . . . . . . . . . . . . 10-54
Different Size . . . . . . . . . . . . . . . 10-70
Dual Rotation . . . . . . . . . . . . . . . 10-67
Full-Size Spare . . . . . . . . . . . . . 10-87
If a Tire Goes Flat . . . . . . . . . . 10-75
Inflation Monitor System . . . . 10-62
Inspection . . . . . . . . . . . . . . . . . . 10-65
Messages . . . . . . . . . . . . . . . . . . . . 5-45
Pressure . . . . . . . . . . . . . . . . . . . . 10-60