Page 369 of 520
A. Engine Air Cleaner/Filter
B. Coolant Surge Tank
C. Air Filter Restriction Indicator (If Equipped)
D. Engine Oil Dipstick
E. Automatic Transmission Dipstick
F. Engine Oil Fill
G. FanH. Remote Negative (−) Terminal (GND)
I. Remote Positive (+) Terminal
J. Power Steering Fluid Reservoir
K. Brake Master Fluid Reservoir
L. Underhood Fuse Block
M. Battery
N. Windshield Washer Fluid Reservoir
5-15
2003 - Yukon/Yukon XL
Page 377 of 520

Automatic Transmission Fluid
When to Check and Change
A good time to check your automatic transmissionfluid
level is when the engine oil is changed.
Change both thefluid andfilter 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 thefluid andfilter every 100,000 miles
(166 000 km).
SeePart A: Scheduled Maintenance Services 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
transmissionfluid 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, thefluid should be at normal
operating temperature, which is 180°Fto200°F
(82°Cto93°C).
5-23
2003 - Yukon/Yukon XL
Page 470 of 520

If the system is ever reset accidentally, you must
change your oil at 3,000 miles (5 000 km) since your
last oil change. Remember to reset the oil life system
whenever the oil is changed. SeeEngine Oil on
page 5-16for information on resetting the system.
An Emission Control Service.
Lubricate chassis components with each engine oil
and filter change.
Lubricate the front suspension, ball joints, steering
linkage, transmission shift linkage, transfer case shift
linkage and parking brake cable guides. Ball joints
should not be lubricated unless their temperature is
10°F(−12°C) or higher, or they could be damaged.
See the mileage intervals following for additional
services that may be performed with an engine oil
change and chassis lubrication. After the services are
performed, record the date, odometer reading and
who performed the service on the maintenance record
pages in Part E of this schedule.7,500 Miles (12 500 km)
❑Check rear/front axlefluid level and addfluid as
needed. Check constant velocity joints and axle seals
for leaking.
❑Rotate tires. SeeTire Inspection and Rotation on
page 5-61for proper rotation pattern and additional
information.(See footnote +.)
15,000 Miles (25 000 km)
❑Inspect engine air cleanerfilter or change indicator (if
equipped). If necessary, replace thefilter. If vehicle is
driven in dusty/dirty conditions, inspectfilter or
change indicator (if equipped) at every engine oil
change. SeeEngine Air Cleaner/Filter on page 5-21
for more information.An Emission Control Service.
(See footnote†.)
❑Check rear/front axlefluid level and addfluid as
needed. Check constant velocity joints and axle seals
for leaking.
❑Rotate tires. SeeTire Inspection and Rotation on
page 5-61for proper rotation pattern and additional
information.(See footnote +.)
6-6
2003 - Yukon/Yukon XL
Page 472 of 520