Page 396 of 556

Black plate (10,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-10 Vehicle Care
Engine Oil Life System
When to Change Engine Oil
This vehicle has a computer system
that indicates when to change the
engine oil and filter. This is based
on a combination of factors which
include engine revolutions, engine
temperature, and miles driven.
Based on driving conditions, the
mileage at which an oil change is
indicated can vary considerably. For
the oil life system to work properly,
the system must be reset every time
the oil is changed.
On some vehicles, when the system
has calculated that oil life has been
diminished, a CHANGE ENGINE
OIL SOON message comes on
to indicate that an oil change is
necessary. SeeEngine Oil
Messages on page 5‑42. Change
the oil as soon as possible within
the next 1 000 km (600 mi). It is
possible that, if driving under the best conditions, the oil life system
might indicate that an oil change is
not necessary for up to a year.
The engine oil and filter must be
changed at least once a year and,
at this time, the system must be
reset. For vehicles without the
CHANGE ENGINE OIL SOON
message, an oil change is
needed when the OIL LIFE
REMAINING percentage is near
0%. Your dealer has trained service
people who will perform this work
and reset the system. It is also
important to check the oil regularly
over the course of an oil drain
interval and keep it at the proper
level.
If the system is ever reset
accidentally, the oil must be
changed at 5 000 km (3,000 mi)
since the last oil change.
Remember to reset the oil life
system whenever the oil is changed.
How to Reset the Engine Oil
Life System
Reset the system whenever the
engine oil is changed so that the
system can calculate the next
engine oil change. Always reset the
engine oil life to 100% after every oil
change. It will not reset itself. To
reset the system on most vehicles:
1. Display the OIL LIFE
REMAINING on the DIC.
If the vehicle does not have
DIC buttons, the vehicle must
be in P (Park) to access this
display. See Driver Information
Center (DIC) on page 5‑30.
2. Press and hold the SET/RESET button on the DIC, or the trip
odometer reset stem if the
vehicle does not have DIC
buttons, for more than
five seconds. The oil life will
change to 100%.
Page 397 of 556

Black plate (11,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-11
On all vehicles, the Engine Oil Life
System can be reset as follows:
1. Turn the ignition to ON/RUN withthe engine off.
2. Fully press the accelerator pedal slowly three times within
five seconds.
3. Display the OIL LIFE REMAINING on the DIC.
If the display shows 100%, the
system is reset. See Driver
Information Center (DIC) on
page 5‑30.
If the vehicle has a CHANGE
ENGINE OIL SOON message and it
comes back on when the vehicle
is started and/or the OIL LIFE
REMAINING is near 0%, the engine
oil life system has not been reset.
Repeat the procedure.Automatic Transmission
Fluid (4-Speed
Transmission)
When to Check and Change
Automatic Transmission Fluid
A good time to check the automatic
transmission fluid level is when the
engine oil is changed.
Change the fluid and filter at the
intervals listed in Maintenance
Schedule on page 11‑3 and be
sure to use the transmission fluid
listed in Recommended Fluids and
Lubricants on page 11‑12.
How to Check Automatic
Transmission Fluid
Because this operation can be a
little difficult, it may be best to have
this done at the dealer service
department.
If not taken to the dealer, be sure to
follow all the instructions here or a
false reading on the dipstick could
result. 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.
Wait at least 30 minutes before
checking the transmission fluid level
if you have been driving:
.When outside temperatures are
above 32°C (90°F).
.At high speed for quite a while.
.In heavy traffic —especially in
hot weather.
.While pulling a trailer.
To get the right reading, the fluid
should be at normal operating
temperature, which is 82°C to 93°C
(180°F to 200°F).
Page 400 of 556

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).