2002 GMC YUKON transfer case

6-29
How to Check Lubricant
Automatic Transfer Case
To get an accurate reading, the vehicle should be on a
level surface.
If the level is below the bottom of the filler plug hole,
you'll need to add some lubricant. Add enough lubricant
to raise the level to the bottom of the filler plug hole.
Use care not to overtighten the plug.What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. See ªRecommended Fluids and
Lubricantsº in the Index.
Front Axle
When to Check Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant. See ªScheduled
Maintenance Servicesº in the Index.

6-76
Fuse Usage
ATC Automatic Transfer Case
RR DEFOG Rear Window Defogger, Heated
Mirrors (Relay)
RTD Autoride
(Real Time Damping)
RR PRK Right Rear Parking Lamps
ECM B PCM
F/PMP Fuel Pump (Relay)
O2 A Oxygen Sensors
O2 B Oxygen Sensors
LR PRK Left Rear Parking Lamps
RR DEFOG Rear Window Defogger,
Heated Mirrors
HDLP Headlamps (Relay)
TRL PRK Parking Lamps Trailer Wiring
PRIME Not Used
RT HDLP Right Headlamps
DRL Daytime Running Lamps (Relay)
HTD MIR Heated MirrorsFuse Usage
LT HDLP Left Headlamps
A/C Air Conditioning
AUX PWR Cigarette Lighter, Auxiliary
Power Outlets
SEO 2 Special Equipment Option Power,
Power Seats, Aux Roof Mnt Lamp
SEO 1 Special Equipment Option
Power, Aux Roof Mnt Lamp,
Cell Phone, OnStar


DRL Daytime Running Lamps
A/C A/C (Relay)
FOG LP Fog Lamps
FOG LP Fog Lamps (Relay)
RADIO Audio System, Instrument Cluster,
Climate Control System
CIGAR Cigarette Lighter, Auxiliary
Power Outlets
RT TURN Right Turn Signals
BTSI Automatic Transmission Shift
Lock Control System

Scheduled Maintenance
7-6Engine Oil and Chassis Lubrication
Scheduled Maintenance
Change engine oil and filter as indicated by the
GM Oil Life System (or every 12 months,
whichever occurs first). Reset the system.
Your vehicle has a computer system that lets you know
when to change the engine oil and filter. This is based on
engine revolutions and engine temperature, and not on
mileage. Based on driving conditions, the mileage at
which an oil change will be indicated can vary
considerably. For the oil life system to work properly,
you must reset the system every time the oil is changed.
When the system has calculated that oil life has been
diminished, it will indicate that an oil change is
necessary. A CHANGE ENGINE OIL message will
come on. Change your oil as soon as possible within the
next two times you stop for fuel. It is possible that, if
you are driving under the best conditions, the oil lifesystem may not indicate that an oil change is necessary
for over a year. However, your engine oil and filter must
be changed at least once a year and at this time the
system must be reset. It is also important to check your
oil regularly and keep it at the proper level.
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. See ªOil Life Systemº in the Index
for 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.

Scheduled Maintenance
7-11
45,000 Miles (75 000 km)

If Equipped: Replace passenger compartment air filter. If you drive regularly
under dusty conditions, the filter may require replacement more often.

Check rear/front axle fluid level and add fluid as needed. Check constant
velocity joints and axle seals for leaking.

Rotate tires. See ªTire Inspection and Rotationº in the Index for proper
rotation pattern and additional information. (See footnote +.)
50,000 Miles (83 000 km)

Change automatic transmission fluid and filter filter if the vehicle's GVWR
is over 8600 lbs. 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 you do not use your vehicle under any of these conditions, change the fluid
and filter at 100,000 miles (166 000 km).
Change transfer case fluid.
ACTUAL
SERVICED BY:MILEAGE
DATE
ACTUAL
SERVICED BY:MILEAGE
DATE

Scheduled Maintenance
7-15
100,000 Miles (166 000 km)

Inspect spark plug wires. An Emission Control Service.

Replace spark plugs. An Emission Control Service.

Change automatic transmission fluid and filter filter if the vehicle's GVWR
is over 8600 lbs. 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 you haven't used your vehicle under severe service conditions listed
previously and, therefore, haven't changed your automatic transmission fluid,
change both the fluid and filter.
Change transfer case fluid.
Except 8.1L V8 Engine: Inspect Positive Crankcase Ventilation (PCV) valve.
An Emission Control Service. ACTUAL
SERVICED BY:MILEAGE
DATE

7-23 Fuel System Inspection
Inspect the complete fuel system for damage or leaks.
Engine Cooling System Inspection
Inspect the hoses and have them replaced if they are
cracked, swollen or deteriorated. Inspect all pipes,
fittings and clamps; replace as needed. Clean the outside
of the radiator and air conditioning condenser. To help
ensure proper operation, a pressure test of the cooling
system and pressure cap is recommended at least once
a year.
Throttle System Inspection
Inspect the throttle system for interference or binding,
and for damaged or missing parts. Replace parts as
needed. Replace any components that have high effort
or excessive wear. Do not lubricate accelerator and
cruise control cables.
Transfer Case and Front Axle
(Four-Wheel Drive) Inspection
Every 12 months or at engine oil change intervals, check
front axle and transfer case and add lubricant when
necessary. A fluid loss could indicate a problem; check
and have it repaired, if needed. On manual shift transfer
case, oil the control lever pivot point. Check vent hose at
transfer case for kinks and proper installation. More
frequent lubrication may be required on off
-road use.
Brake System Inspection
Inspect the complete system. Inspect brake lines and
hoses for proper hook
-up, binding, leaks, cracks,
chafing, etc. Inspect disc brake pads for wear and rotors
for surface condition. Inspect other brake parts,
including calipers, parking brake, etc. You may need to
have your brakes inspected more often if your driving
habits or conditions result in frequent braking.

7-25
USAGEFLUID/LUBRICANT
Floor
Shift LinkageLubriplate
Lubricant Aerosol
(GM Part No. 12346293 or
equivalent) or lubricant meeting
requirements of NLGI # 2
Category LB or GC
-LB.
Chassis
LubricationChassis Lubricant (GM Part
No. 12377985 or equivalent)
or lubricant meeting requirements
of NLGI # 2, Category LB
or GC
-LB.
Front AxleSAE 80W-90 Axle Lubricant
(GM Part No. 1052271
or equivalent).
Rear AxleSAE 75W-90 Synthetic
Axle Lubricant (GM Part
No. 12378261) or
equivalent meeting
GM Specification 9986115.
USAGEFLUID/LUBRICANT
Transfer CaseAUTO-TRAK II Fluid
(GM Part No. 12378508).
Front Axle
Propshaft Spline
or One
-Piece
Propshaft Spline
(Two
-Wheel
Drive with
Auto. Trans.)
Spline Lubricant,
Special Lubricant (GM Part
No. 12345879) or lubricant
meeting requirements
of GM 9985830.
Hood Latch
Assembly,
Secondary Latch,
Pivots, Spring
Anchor and
Release PawlLubriplate
Lubricant Aerosol
(GM Part No. 12346293 or
equivalent) or lubricant meeting
requirements of NLGI # 2,
Category LB or GC
-LB.

8-12
SERVICE PUBLICATIONS ORDERING INFORMATION
Service Manuals
Service Manuals have the diagnosis and repair
information on engines, transmission, axle, suspension,
brakes, electrical, steering, body, etc.
RETAIL SELL PRICE: $120.00
Transmission, Transaxle, Transfer Case
Unit Repair Manual
This manual provides information on unit repair
service procedures, adjustments and specifications
for GM transmissions, transaxles and transfer cases.
RETAIL SELL PRICE: $50.00
Service Bulletins
Service Bulletins give technical service information
needed to knowledgeably service General Motors cars
and trucks. Each bulletin contains instructions to assist
in the diagnosis and service of your vehicle.
Owner's Information
Owner publications are written specifically for owners
and intended to provide basic operational information
about the vehicle. The owner's manual will include the
Maintenance Schedule for all models.
In
-Portfolio: Includes a Portfolio, Owner's Manual and
Warranty Booklet.
RETAIL SELL PRICE: $35.00
Without Portfolio: Owner's Manual only.
RETAIL SELL PRICE: $25.00
Current and Past Model Order Forms
Service Publications are available for current and
past model GM vehicles. To request an order form,
please specify year and model name of the vehicle.
ORDER TOLL FREE: 1-800-551-4123 ± Monday-Friday 8:00 AM ± 6:00 PM Eastern TimeVisit Helm, Inc. on the World Wide Web at: www.helminc.com For Credit Card Orders Only (VISA-MasterCard-Discover)
Helm, Incorporated
P.O. Box 07130
Detroit, MI 48207
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