2010 GMC YUKON engine

3. Remove the engine air cleaner/filter from thehousing. Care should be taken to dislodge as little
dirt as possible. 4. Clean the engine air cleaner/filter sealing surfaces
and the housing.
5. Inspect or replace the engine air cleaner/filter.
6. Reinstall the cover and tighten the screws.
{WARNING:
Operating the engine with the air cleaner/filter off
can cause you or others to be burned. The air
cleaner not only cleans the air; it helps to stop
flames if the engine backfires. Use caution when
working on the engine and do not drive with the
air cleaner/filter off.
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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
Scheduled Maintenance
on page 7‑3and be sure
to use the transmission fluid listed in Recommended
Fluids and Lubricants on page 7‑11.
How to Check Automatic Transmission
Fluid
Because this operation can be a little difficult, you
may choose to have this done at the dealer service
department.
If you do it yourself, be sure to follow all the instructions
here or you could get a false reading on the dipstick.
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).
Get the vehicle warmed up by driving about
24 km (15 miles) when outside temperatures are above
10°C (50°F). If it is colder than 10°C (50°F), drive the
vehicle in 3 (Third) until the engine temperature gauge
moves and then remains steady for 10 minutes.
A cold fluid check can be made after the vehicle has
been sitting for eight hours or more with the engine off,
but this is used only as a reference. Let the engine
run at idle for five minutes if outside temperatures are
10°C (50°F) or more. If it is colder than 10°C (50°F),
you may have to idle the engine longer. Should the fluid
level be low during this cold check, you must check the
fluid hot before adding fluid. Checking the fluid hot will
give you a more accurate reading of the fluid level.
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Checking the Fluid Level
Prepare the vehicle as follows:1. Park the vehicle on a level place. Keep the engine running.
2. With the parking brake applied, 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, position the
shift lever in P (Park).
4. Let the engine run at idle for three minutes or more. Then, without shutting off the engine, follow these
steps:1. Locate the
transmission
dipstick handle
with this graphic
which is located at
the rear of the engine
compartment, on the
passenger side of the
vehicle.
See Engine Compartment Overview
on page 6‑16for more information on location.
2. Flip the handle up and then pull out the dipstick and wipe it with a clean rag or paper towel.
3. Push it back in all the way, wait three seconds and then pull it back out again.
6-25

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 overheating the transmission.
If you suspect a small leak, 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's warranty. Always
use the automatic transmission fluid listed in
Recommended Fluids and Lubricants on page 7‑11.
Change the fluid and filter at the intervals listed in the
Maintenance Schedule. See Scheduled Maintenance
on page 7‑3. Be sure to use the transmission fluid
listed in Recommended Fluids and Lubricantson
page 7‑11.
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).
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4. Allow the engine to idle (500–800 rpm) for at least
one 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).
6. Using the TRANS TEMP reading, 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 6‑16for more information.
2. Flip the handle up, and 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.
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5. If the fluid level is below the COLD 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.
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 thetransmission dipstick at
the rear of the engine
compartment, on the
passenger side of the
vehicle.
See Engine Compartment Overview
on page 6‑16for more information.
2. Flip the handle up, and 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.
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5. Safe operating level is within the HOT cross hatchband 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 Liter (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 your
dealer.
Cooling System
If the vehicle is a Two-mode Hybrid, see the Two-mode
Hybrid manual for more information.
The cooling system allows the engine to maintain the
correct working temperature.
6-30

5.3L Engine shown, 6.0L and 6.2L Engine similar
A. Coolant Surge Tank
B. Coolant Surge Tank Pressure Cap
C. Engine Cooling Fan(s)
{WARNING:
An electric engine cooling fan under the hood can
start up even when the engine is not running and
can cause injury. Keep hands, clothing, and tools
away from any underhood electric fan.
{WARNING:
Heater and radiator hoses, and other engine
parts, can be very hot. Do not touch them. If you
do, you can be burned.
Do not run the engine if there is a leak. If you run
the engine, it could lose all coolant. That could
cause an engine fire, and you could be burned.
Get any leak fixed before you drive the vehicle.
Notice: Using coolant other than DEX-COOL
®can
cause premature engine, heater core, or radiator
corrosion. In addition, the engine coolant could
require changing sooner, at 50 000 km (30,000 miles)
or 24 months, whichever occurs first. Any repairs
would not be covered by the vehicle warranty.
Always use DEX-COOL
®(silicate-free) coolant in
the vehicle.
6-31