2004 GMC YUKON automatic transmission

Driving On Grades
Reduce speed and shift to a lower gearbeforeyou start
down a long or steep downgrade. If you don’t shift
down, you might have to use your brakes so much that
they would get hot and no longer work well.
You can tow in DRIVE (D). You may want to shift the
transmission to THIRD (3) or, if necessary, a lower gear
selection if the transmission shifts too often (e.g.,
under heavy loads and/or hilly conditions).
You may also want to activate the tow/haul mode if the
transmission shifts too often. See “Tow/Haul Mode”
earlier in this section for more information.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a lower
temperature than at normal altitudes. If you turn your
engine off immediately after towing at high altitude on
steep uphill grades, your vehicle may show signs similar
to engine overheating. To avoid this, let the engine run
while parked (preferably on level ground) with the
automatic transmission in PARK (P) for a few minutes
before turning the engine off. If you do get the overheat
warning, seeEngine Overheating on page 5-29.
Parking on Hills
{CAUTION:
You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But if you ever have to park your rig on a hill, here’s
how to do it:
1. Apply your regular brake, but don’t shift into
PARK (P) yet.
2. Have someone place chocks under the trailer
wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your
parking brake and shift into PARK (P).
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5. If you have a four-wheel-drive vehicle, be sure the
transfer case is in a drive gear and not in
NEUTRAL.
6. Release the regular brakes.
{CAUTION:
It can be dangerous to get out of your vehicle if
the shift lever is not fully in PARK (P) with the
parking brake rmly set. Your vehicle can roll.
If you have left the engine running, the vehicle
can move suddenly. You or others could be
injured. To be sure your vehicle will not move,
even when you are on fairly level ground, use
the steps that follow.
Always put the shift lever fully in PARK (P) with
the parking brake rmly set.
If the transfer case on four-wheel-drive vehicles
is in NEUTRAL, your vehicle will be free to roll,
even if your shift lever is in PARK (P). So, be
sure the transfer case is in a drive gear — not in
NEUTRAL.
When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:
start your engine,
shift into a gear, and
release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the
chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you’re
pulling a trailer. See the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transmission uid (don’t overll),
engine oil, axle lubricant, belts, cooling system and brake
system. Each of these is covered in this manual, and the
Index will help you nd them quickly. If you’re trailering,
it’s a good idea to review these sections before you start
your trip.
Check periodically to see that all hitch nuts and bolts
are tight.
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Service............................................................5-3
Doing Your Own Service Work.........................5-3
Adding Equipment to the Outside of Your
Vehicle......................................................5-4
Fuel................................................................5-4
Gasoline Octane............................................5-4
Gasoline Specications....................................5-5
California Fuel...............................................5-5
Additives.......................................................5-6
Fuel E-85 (85% Ethanol).................................5-6
Fuels in Foreign Countries...............................5-8
Filling Your Tank............................................5-8
Filling a Portable Fuel Container.....................5-10
Checking Things Under the Hood....................5-10
Hood Release..............................................5-11
Engine Compartment Overview.......................5-12
Engine Oil...................................................5-16
Engine Air Cleaner/Filter................................5-21
Automatic Transmission Fluid.........................5-23
Engine Coolant.............................................5-26
Coolant Surge Tank Pressure Cap..................5-28
Engine Overheating.......................................5-29Cooling System............................................5-32
Engine Fan Noise.........................................5-38
Power Steering Fluid.....................................5-38
Windshield Washer Fluid................................5-40
Brakes........................................................5-41
Battery........................................................5-44
Jump Starting...............................................5-45
All-Wheel Drive..............................................5-51
Rear Axle.......................................................5-52
Four-Wheel Drive............................................5-53
Front Axle......................................................5-54
Bulb Replacement..........................................5-55
Halogen Bulbs..............................................5-55
Headlamps..................................................5-55
Front Turn Signal, Sidemarker and Daytime
Running Lamps.........................................5-56
Side Identication Marker Lamps.....................5-57
Roof Marker Lamps......................................5-58
Taillamps.....................................................5-60
Replacement Bulbs.......................................5-61
Section 5 Service and Appearance Care
5-1

A. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-21.
B. Coolant Surge Tank. SeeCooling System on
page 5-32.
C. Air Filter Restriction Indicator (If Equipped). See
Engine Air Cleaner/Filter on page 5-21.
D. Engine Oil Dipstick. SeeEngine Oil on page 5-16.
E. Automatic Transmission Dipstick. SeeAutomatic
Transmission Fluid on page 5-23.
F. Engine Oil Fill. SeeEngine Oil on page 5-16.
G. Fan. SeeCooling System on page 5-32.
H. Remote Negative (−) Terminal (GND). SeeJump
Starting on page 5-45.I. Power Steering Fluid Reservoir. SeePower Steering
Fluid on page 5-38.
J. Remote Positive (+) Terminal. SeeJump Starting on
page 5-45.
K. Brake Master Cylinder Reservoir. SeeBrakes on
page 5-41.
L. Underhood Fuse Block. SeeFuses and Circuit
Breakers on page 5-113.
M. Battery. SeeBattery on page 5-44.
N. Windshield Washer Fluid Reservoir. SeeWindshield
Washer Fluid on page 5-40.
5-13

A. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-21.
B. Coolant Surge Tank. SeeCooling System on
page 5-32.
C. Air Filter Restriction Indicator (If Equipped). See
Engine Air Cleaner/Filter on page 5-21.
D. Engine Oil Dipstick. SeeEngine Oil on page 5-16.
E. Automatic Transmission Dipstick. SeeAutomatic
Transmission Fluid on page 5-23.
F. Engine Oil Fill. SeeEngine Oil on page 5-16.
G. Fan. SeeCooling System on page 5-32.
H. Remote Negative (−) Terminal (GND). SeeJump
Starting on page 5-45.I. Remote Positive (+) Terminal. SeeJump Starting on
page 5-45.
J. Power Steering Fluid Reservoir. SeePower Steering
Fluid on page 5-38.
K. Brake Master Fluid Reservoir. SeeBrakes on
page 5-41.
L. Underhood Fuse Block. SeeFuses and Circuit
Breakers on page 5-113.
M. Battery. SeeBattery on page 5-44.
N. Windshield Washer Fluid Reservoir. SeeWindshield
Washer Fluid on page 5-40.
5-15

Automatic Transmission Fluid
When to Check and Change
A good time to check your automatic transmission uid
level is when the engine oil is changed.
Change both the uid and lter every 50,000 miles
(83 000 km) if the vehicle’s GVWR is over 8,600 or if
the vehicle is mainly driven under one or more of these
conditions:
In heavy city traffic where the outside temperature
regularly reaches 90°F (32°C) or higher.
In hilly or mountainous terrain.
When doing frequent trailer towing.
Uses such as found in taxi, police or delivery
service.
If your vehicle’s GVWR is not over 8,600 and you do
not use your vehicle under any of these conditions,
change the uid and lter every 100,000 miles
(166 000 km).
SeeScheduled Maintenance on page 6-4.
How to Check
Because this operation can be a little difficult, you may
choose to have this done at the dealership 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
part 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).
5-23

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 area 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.
How to Add Fluid
Refer to the Maintenance Schedule to determine what
kind of transmission uid to use. SeeRecommended
Fluids and Lubricants on page 6-12.
Add uid 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 doesn’t take much uid, generally less than one
pint (0.5 L).Don’t overll.
Notice:We recommend you use only uid labeled
DEXRON
®-III, because uid with that label is
made especially for your automatic transmission.
Damage caused by uid other than DEXRON
®-III is
not covered by your new vehicle warranty.
After adding uid, recheck the uid level as
described underHow to Check.
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.
5-25

1. Check the other vehicle. It must have a 12-volt
battery with a negative ground system.
Notice:If the other vehicle’s system is not a 12-volt
system with a negative ground, both vehicles can
be damaged. Only use vehicles with 12-volt systems
with negative grounds to jump start your vehicle.
2. Get the vehicles close enough so the jumper cables
can reach, but be sure the vehicles aren’t touching
each other. If they are, it could cause a ground
connection you don’t want. You wouldn’t 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 rmly on both vehicles involved in
the jump start procedure. Put the automatic
transmission in PARK (P) 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 you leave your radio or other accessories
on during the jump starting procedure, they could
be damaged. The repairs would not be covered
by your warranty. Always turn off your radio and
other accessories when jump starting your vehicle.3. Turn off the ignition on both vehicles. Unplug
unnecessary accessories plugged into the cigarette
lighter or in the accessory power outlets. Turn off
the radio and all the lamps that aren’t needed. This
will avoid sparks and help save both batteries.
And it could save your radio!
4. Open the hoods and locate the positive (+) and
negative (−) terminal locations of the other vehicle.
Your vehicle has a remote positive (+) jump
starting terminal and a remote negative (−) jump
starting terminal. You should always use these
remote terminals instead of the terminals on the
battery.
The remote positive (+) terminal is located behind a
red plastic cover, if equipped, near the engine
accessory drive bracket. To uncover the remote
positive (+) terminal, open the red plastic cover, if
equipped.
The remote negative (−) terminal is located on the
engine drive bracket, or on the thermostat
housing on the 8.1L engine. It is marked″GND.″
SeeEngine Compartment Overview on page 5-12
for more information on location.
5-46