2008 GMC YUKON check transmission fluid

Service............................................................5-3
Accessories and Modications..........................5-3
California Proposition 65 Warning.....................5-4
California Perchlorate Materials Requirements.....5-4
Doing Your Own Service Work.........................5-4
Adding Equipment to the Outside of Your
Vehicle......................................................5-5
Fuel................................................................5-5
Gasoline Octane............................................5-5
Gasoline Specications....................................5-6
California Fuel...............................................5-6
Additives.......................................................5-6
Fuel E85 (85% Ethanol)..................................5-7
Fuels in Foreign Countries...............................5-8
Filling the Tank..............................................5-9
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...................................................5-15
Engine Oil Life System..................................5-18
Engine Air Cleaner/Filter................................5-19
Automatic Transmission Fluid
(4-Speed Transmission)..............................5-22
Automatic Transmission Fluid
(6-Speed Transmission)..............................5-24
Engine Coolant.............................................5-28Coolant Surge Tank Pressure Cap..................5-31
Engine Overheating.......................................5-31
Overheated Engine Protection
Operating Mode........................................5-33
Cooling System............................................5-34
Engine Fan Noise.........................................5-39
Power Steering Fluid.....................................5-39
Windshield Washer Fluid................................5-40
Brakes........................................................5-41
Battery
........................................................5-45
Jump Starting...............................................5-46
Rear Axle.......................................................5-52
Four-Wheel Drive............................................5-54
Front Axle......................................................5-55
Headlamp Aiming...........................................5-56
Bulb Replacement..........................................5-59
Halogen Bulbs..............................................5-59
Taillamps, Turn Signal, Stoplamps and
Back-up Lamps.........................................5-60
License Plate Lamp......................................5-61
Replacement Bulbs.......................................5-61
Windshield Wiper Blade Replacement..............5-62
Tires..............................................................5-64
Tire Sidewall Labeling...................................5-65
Tire Terminology and Denitions.....................5-69
Ination - Tire Pressure.................................5-72
Section 5 Service and Appearance Care
5-1

A. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-19.
B. Air Filter Restriction Indicator (If Equipped). See
Engine Air Cleaner/Filter on page 5-19.
C. Coolant Surge Tank and Pressure Cap. SeeCooling
System on page 5-34andCoolant Surge Tank
Pressure Cap on page 5-31.
D. Remote Positive (+) Terminal. SeeJump Starting on
page 5-46.
E. Battery. SeeBattery on page 5-45.
F. Engine Oil Fill Cap. See “When to Add Engine Oil”
underEngine Oil on page 5-15.
G. Automatic Transmission Dipstick. See “Checking the
Fluid Level” underAutomatic Transmission Fluid
(4-Speed Transmission) on page 5-22orAutomatic
Transmission Fluid (6-Speed Transmission) on
page 5-24.
H. Remote Negative (−) Terminal (Out of View). See
Jump Starting on page 5-46.
I. Engine Oil Dipstick (Out of View). See “Checking
Engine Oil” underEngine Oil on page 5-15.
J. Engine Cooling Fan. SeeCooling System on
page 5-34.
K. Power Steering Fluid Reservoir. SeePower Steering
Fluid on page 5-39.L. Brake Master Cylinder Reservoir. See “Brake Fluid”
underBrakes on page 5-41.
M. Underhood Fuse Block. SeeUnderhood Fuse Block
on page 5-120.
N. Windshield Washer Fluid Reservoir. See “Adding
Washer Fluid” underWindshield Washer Fluid
on page 5-40.
Engine Oil
Checking Engine Oil
It is a good idea to check the engine oil every time you
get fuel. In order to get an accurate reading, the oil
must be warm and the vehicle must be on level ground.
The engine oil dipstick handle is a yellow loop. See
Engine Compartment Overview on page 5-14for
the location of the engine oil dipstick.
1. Turn off the engine and give the oil several minutes
to drain back into the oil pan. If you do not do this,
the oil dipstick might not show the actual level.
2. Pull out the dipstick and clean it with a paper towel
or cloth, then push it back in all the way. Remove it
again, keeping the tip down, and check the level.
5-15

Automatic Transmission Fluid
(4-Speed Transmission)
When to Check and Change Automatic
Transmission Fluid
A good time to check your automatic transmission uid
level is when the engine oil is changed.
Change the uid and lter at the intervals listed in
Additional Required Services on page 6-6, and be sure
to use the transmission uid listed inRecommended
Fluids and Lubricants on page 6-13.
How to Check Automatic
Transmission Fluid
Because this operation can be a little difficult, you may
choose to have this done at the dealer/retailer 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 uid can damage
your transmission. Too much can mean that some
of the uid could come out and fall on hot engine
parts or exhaust system parts, starting a re.
Too little uid could cause the transmission to
overheat. Be sure to get an accurate reading if you
check your transmission uid.Wait at least 30 minutes before checking the
transmission uid level if you have been driving:
When outside temperatures are above 90°F (32°C).
At high speed for quite a while.
In heavy traffic — especially in hot weather.
While pulling a trailer.
To get the right reading, the uid should be at normal
operating temperature, which is 180°F to 200°F
(82°C to 93°C).
Get the vehicle warmed up by driving about 15 miles
(24 km) when outside temperatures are above 50°F
(10°C). If it is colder than 50°F (10°C), drive the vehicle
in THIRD (3) until the engine temperature gage
moves and then remains steady for 10 minutes.
A cold uid 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 ve minutes if outside temperatures are
50°F (10°C) or more. If it is colder than 50°F (10°C), you
may have to idle the engine longer. Should the uid
level be low during this cold check, you must check the
uid hot before adding uid. Checking the uid hot
will give you a more accurate reading of the uid level.
5-22

Checking the Fluid Level
Prepare your vehicle as follows:
1. Park your vehicle on a level place. Keep the engine
running.
2. With the parking brake applied, place the shift lever
in PARK (P).
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 PARK (P).
4. Let the engine run at idle for three minutes or more.
Then, without shutting off the engine, follow these steps:
The transmission dipstick
handle with this graphic is
located at the rear of
the engine compartment,
on the passenger’s
side of the vehicle.SeeEngine Compartment Overview on page 5-14for
more information on location.
1. Flip the handle up and then pull out the dipstick
and wipe it with a clean rag or paper towel.
2. Push it back in all the way, wait three seconds and
then pull it back out again.
3. Check both sides of the dipstick, and read the lower
level. The uid level must be in the COLD area,
below the cross-hatched area, for a cold check or in
the HOT or cross-hatched area for a hot check.
Be sure to keep the dipstick pointed down to get an
accurate reading.
4. If the uid level is in the acceptable range, push the
dipstick back in all the way; then ip the handle
down to lock the dipstick in place.
5-23

Consistency of Readings
Always check the uid level at least twice using the
procedure described previously. Consistency (repeatable
readings) is important to maintaining proper uid
level. If readings are still inconsistent, contact your
dealer/retailer.
How to Add Automatic
Transmission Fluid
Refer to the Maintenance Schedule to determine what
kind of transmission uid to use. SeeRecommended
Fluids and Lubricants on page 6-13.
Using a funnel, add uid down the transmission dipstick
tube only after checking the transmission uid while it
is hot. A cold check is used only as a reference. If
the uid level is low, add only enough of the proper uid
to bring the level up to the HOT area for a hot check.
It does not take much uid, generally less than one pint
(0.5 L). Do not overll.Notice:Use of the incorrect automatic transmission
uid may damage your vehicle, and the damages
may not be covered by your warranty. Always
use the automatic transmission uid listed in
Recommended Fluids and Lubricants on page 6-13.
After adding uid, recheck the uid level as
described under “How to Check Automatic
Transmission Fluid,” earlier in this section.
When the correct uid level is obtained, push the
dipstick back in all the way; then ip the handle
down to lock the dipstick in place.
Automatic Transmission Fluid
(6-Speed Transmission)
When to Check and Change Automatic
Transmission Fluid
It is usually not necessary to check the transmission
uid level. The only reason for uid loss is a
transmission leak or overheating the transmission. If you
suspect a small leak, then use the following checking
procedures to check the uid level. However, if there is a
large leak, then it may be necessary to have the
vehicle towed to a dealer/retailer service department
and have it repaired before driving the vehicle further.
5-24

Notice:Use of the incorrect automatic transmission
uid may damage your vehicle, and the damages
may not be covered by your warranty. Always
use the automatic transmission uid listed in
Recommended Fluids and Lubricants on page 6-13.
Change the uid and lter at the intervals listed in
the Maintenance Schedule. SeeScheduled Maintenance
on page 6-4. Be sure to use the transmission uid
listed inRecommended Fluids and Lubricants on
page 6-13.
How to Check Automatic
Transmission Fluid
Notice:Too much or too little uid can damage
your transmission. Too much can mean that some
of the uid could come out and fall on hot engine
parts or exhaust system parts, starting a re.
Too little uid could cause the transmission to
overheat. Be sure to get an accurate reading if you
check your transmission uid.Before checking the uid level, prepare your vehicle as
follows:
1. Start the engine and park your vehicle on a level
surface. Keep the engine running.
2. Apply the parking brake and place the shift lever in
PARK (P).
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 PARK (P).
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 uid temperature is reached.
5-25

Engine Fan Noise
If your vehicle has a clutched engine cooling fan, when
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions, the fan is spinning slower and the clutch is
not fully engaged. This improves fuel economy and
reduces fan noise. Under heavy vehicle loading, trailer
towing, and/or high outside temperatures, the fan
speed increases as the clutch more fully engages, so
you may hear an increase in fan noise. 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.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch partially
disengages.
If your vehicle has electric cooling fans, you may hear
the fans spinning at low speed during most everyday
driving. The fans may turn off if no cooling is required.
Under heavy vehicle loading, trailer towing, and/or
high outside temperatures, or if you are operating your
air conditioning system, the fans may change to
high speed and you may hear an increase in fan noise.
This is normal and indicates that the cooling system
is functioning properly. The fans will change to low
speed when additional cooling is no longer required.
Power Steering Fluid
SeeEngine Compartment
Overview on page 5-14for
reservoir location.
If your vehicle is a
Two-mode Hybrid, see
the Two-mode Hybrid
manual for more
information.
When to Check Power Steering Fluid
It is not necessary to regularly check power steering uid
unless you suspect there is a leak in the system or
you hear an unusual noise. A uid loss in this system
could indicate a problem. Have the system inspected
and repaired.
5-39

ApplicationCapacities
English Metric
6L90-Transmission 6.3 qt 6.0 L
Transfer Case Fluid 2.0 qt 1.9 L
Wheel Nut Torque 140 lb ft 190Y
†Oil lter should be changed at every oil change.
After rell, the level must be rechecked. Add enough engine coolant so that the uid is within the proper operating
range.
Engine Specications
Engine VIN Code Transmission Spark Plug Gap
4.8L V8 C Automatic 0.040 in (1.01 mm)
5.3L V8 Flexible Fuel with
Active Fuel Management™
(Iron Block)0 Automatic 0.040 in (1.01 mm)
5.3L V8 Flexible Fuel with
Active Fuel Management™
(Aluminum Block)3 Automatic 0.040 in (1.01 mm)
5.3L V8 with Active Fuel
Management™ (Iron Block)J Automatic 0.040 in (1.01 mm)
6.0L V8 (Iron Block) K Automatic 0.040 in (1.01 mm)
6.0L V8 with Active Fuel
Management™
(Aluminum Block)Y Automatic 0.040 in (1.01 mm)
5-125