2012 GMC SIERRA 1500 automatic transmission

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 (35,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-35
Starter Switch Check
{WARNING
When you are doing this
inspection, the vehicle could
move suddenly. If the vehicle
moves, you or others could be
injured.
1. Before starting this check, be sure there is enough room
around the vehicle.
2. Firmly apply both the parking brake and the regular brake.
See Parking Brake on
page 9‑54.
Do not use the accelerator
pedal, and be ready to turn off
the engine immediately if it
starts.
3. Try to start the engine in each gear. The vehicle should start
only in P (Park) or N (Neutral). If the vehicle starts in any other
position, contact your dealer for
service.Automatic Transmission
Shift Lock Control
Function Check
{WARNING
When you are doing this
inspection, the vehicle could
move suddenly. If the vehicle
moves, you or others could be
injured.
1. Before starting this check, be sure there is enough room
around the vehicle. It should be
parked on a level surface.
2. Firmly apply the parking brake. See Parking Brake on
page 9‑54.
Be ready to apply the regular
brake immediately if the vehicle
begins to move. 3. With the engine off, turn the
ignition on, but do not start the
engine. Without applying the
regular brake, try to move the
shift lever out of P (Park) with
normal effort. If the shift lever
moves out of P (Park), contact
your dealer for service.
Ignition Transmission
Lock Check
While parked, and with the parking
brake set, try to turn the ignition to
LOCK/OFF in each shift lever
position.
.The ignition should turn to
LOCK/OFF only when the shift
lever is in P (Park).
.The ignition key should come
out only in LOCK/OFF.
Contact your dealer if service is
required.

Black plate (55,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-55
Light Truck (LT‐Metric) Tire
(A) Light Truck (LT‐Metric)
Tire
:The United States version
of a metric tire sizing system.
The letters LT as the first two
characters in the tire size mean
a light truck tire engineered to
standards set by the U.S. Tire
and Rim Association.
(B) Tire Width
:The three‐digit
number indicates the tire section
width in millimeters from
sidewall to sidewall.
(C) Aspect Ratio
:A two‐digit
number that indicates the tire
height‐to‐width measurements.
For example, if the tire size
aspect ratio is 75, as shown
in item C of the light truck (LT‐Metric) tire illustration, it
would mean that the tire's
sidewall is 75 percent as high
as it is wide.
(D) Construction Code
:A
letter code is used to indicate
the type of ply construction in
the tire. The letter R means
radial ply construction; the
letter D means diagonal or
bias ply construction; and the
letter B means belted‐bias ply
construction.
(E) Rim Diameter
:Diameter of
the wheel in inches.
(F) Load Range
:Load Range.
(G) Service Description
:The
service description indicates the
load index and speed rating of a
tire. If two numbers are given as
in the example, 120/116, then
this represents the load index for
single versus dual wheel usage (single/dual). The speed rating is
the maximum speed a tire is
certified to carry a load.
Tire Terminology and
Definitions
Air Pressure:The amount
of air inside the tire pressing
outward on each square inch
of the tire. Air pressure is
expressed in kPa (kilopascal)
or psi (pounds per square inch).
Accessory Weight
:The
combined weight of optional
accessories. Some examples
of optional accessories are
automatic transmission, power
steering, power brakes, power
windows, power seats, and air
conditioning.
Aspect Ratio
:The relationship
of a tire's height to its width.

Black plate (76,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-76 Vehicle Care
Turn on the hazard warning
flashers. SeeHazard Warning
Flashers on page 6‑5.
{WARNING
Changing a tire can be
dangerous. The vehicle can slip
off the jack and roll over or fall
causing injury or death. Find a
level place to change the tire. To
help prevent the vehicle from
moving:
1. Set the parking brake firmly.
2. Put an automatic transmission in P (Park) or
a manual transmission in
1 (First) or R (Reverse).
3. For four-wheel-drive vehicles, be sure the
transfer case is in a drive
gear– not in N (Neutral).
4. Turn off the engine and do not restart while the vehicle
is raised.
(Continued)
WARNING (Continued)
5. Do not allow passengers toremain in the vehicle.
6. Place wheel blocks on both sides of the tire at the
opposite corner of the tire
being changed.
When the vehicle has a flat tire (B),
use the following example as a
guide to assist in the placement of
the wheel blocks (A).
A. Wheel Block
B. Flat Tire The following information explains
how to use the jack and change
a tire.
Tire Changing
Removing the Spare Tire and
Tools
Crew Cab
A. Wing Nut Retaining Tool Kit
B. Tool Kit
C. Wheel Blocks
D. Jack

Black plate (89,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-89
get enough power from a single
battery in another vehicle to
start your diesel engine. If your
vehicle has more than one
battery, using the battery that is
closer to the starter will reduce
electrical resistance. This is
located on the passenger side,
in the rear of the engine
compartment.
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 an unwanted
ground connection. 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 firmly on both vehicles
involved in the jump start
procedure. Put the automatic
transmission in P (Park) 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 any accessories are left
on or plugged in during the jump
starting procedure, they could be
damaged. The repairs would not
be covered by the vehicle
warranty. Whenever possible,
turn off or unplug all accessories
on either vehicle when jump
starting the vehicle. 4. Turn off the ignition on both
vehicles. Unplug unnecessary
accessories plugged into the
accessory power outlets. Turn
off the radio and all the lamps
that are not needed. This will
avoid sparks and help save both
batteries. And it could save the
radio!
5. Open the hood on the other vehicle and locate the
positive (+) and negative (−)
terminal locations on that
vehicle.
The positive (+) terminal, is
located under a red plastic cover
at the positive battery post. To
uncover the positive (+) terminal,
open the red plastic cover.

Black plate (4,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
11-4 Service and Maintenance
.Visually inspect steering,
suspension, and chassis
components for damaged, loose,
or missing parts or signs of
wear. SeeExterior Care on
page 10‑98.
.Check restraint system
components. See Safety System
Check on page 3‑20.
.Visually inspect fuel system for
damage or leaks.
.Visually inspect exhaust system
and nearby heat shields for
loose or damaged parts.
.Lubricate body components. See
Exterior Care on page 10‑98.
.Check starter switch. See Starter
Switch Check on page 10‑35.
.Check automatic transmission
shift lock control function. See
Automatic Transmission Shift
Lock Control Function Check on
page 10‑35.
.Check ignition transmission lock.
See Ignition Transmission Lock
Check on page 10‑35.
.Check parking brake and
automatic transmission park
mechanism. See Park Brake and
P (Park) Mechanism Check on
page 10‑36.
.Check accelerator pedal for
damage, high effort, or binding.
Replace if needed.
.Visually inspect gas strut for
signs of wear, cracks, or other
damage. Check the hold open
ability of the strut. See your
dealer if service is required.
.Inspect sunroof track and seal,
if equipped. See Sunroof (Crew
Cab) on page 2‑23 orSunroof
(Extended Cab) on page 2‑22.
.Check hybrid low pressure
coolant level, if equipped.

Black plate (12,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
11-12 Service and Maintenance
Recommended Fluids, Lubricants, and Parts
Recommended Fluids and Lubricants
This maintenance section applies to vehicles with a gasoline engine. If the vehicle has a diesel engine and/or an
Allison Transmission, see the maintenance schedule section in the DURAMAX® Diesel supplement.
Fluids and lubricants identified below by name, part number, or specification can be obtained from your dealer.Usage Fluid/Lubricant
Engine Oil Use only engine oil licensed to the dexos1 specfication, or equivalent, of
the proper SAE viscosity grade. ACDelco dexos1 Synthetic Blend is
recommended. See
Engine Oil on page 10‑7.
Engine Coolant 50/50 mixture of clean, drinkable water and use only DEX-COOL coolant.
See
Engine Coolant on page 10‑19.
Hydraulic Brake System DOT 3 Hydraulic Brake Fluid (GM Part No. 12377967, in
Canada 89021320).
Windshield Washer Automotive windshield washer fluid that meets regional freeze protection
requirements.
Power Steering System GM Power Steering Fluid (GM Part No. 89021184, in Canada 89021186).
Automatic Transmission DEXRON®-VI Automatic Transmission Fluid.
Key Lock Cylinders Multi-Purpose Lubricant, Superlube (GM Part No. 12346241, in
Canada 10953474).

Black plate (13,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Service and Maintenance 11-13
UsageFluid/Lubricant
Floor Shift Linkage Lubriplate Lubricant Aerosol (GM Part No. 12346293, in Canada 992723)
or lubricant meeting requirements of NLGI #2 Category LB or GC-LB.
Chassis Lubrication Chassis Lubricant (GM Part No. 12377985, in Canada 88901242) or
lubricant meeting requirements of NLGI #2, Category LB or GC-LB.
Front Axle
(1500 Series) - Four-Wheel Drive SAE 80W-90 Axle Lubricant (GM Part No. 89021671, in
Canada 89021672).
Front Axle (1500, 2500 HD, and 3500 HD Series) SAE 75W-90 Synthetic Axle Lubricant (GM Part No. 89021677, in
Canada 89021678).
Rear Axle SAE 75W-90 Synthetic Axle Lubricant (GM Part No. 89021677, in
Canada 89021678).
Transfer Case (Four-Wheel Drive) DEXRON®-VI Automatic Transmission Fluid. Front Axle Propshaft Spline orOne-Piece Propshaft Spline
(Two-Wheel Drive with 4-Speed Auto. Trans.) Spline Lubricant, Special Lubricant (GM Part No. 12345879, in
Canada 10953511).
Rear Driveline Center Spline Chassis Lubricant (GM Part No. 12377985, in Canada 88901242) or
lubricant meeting requirements of NLGI #2, Category LB or GC-LB.