1999 GMC YUKON transfer case

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NOTICE:
Spinning your wheels can destroy parts of your
vehicle as well as the tires. If you spin the wheels
too fast while shifting your transmission back
and forth, you can destroy your transmission.
For information about using tire chains on your vehicle,
see ªTire Chainsº in the Index.
Rocking Your Vehicle To Get It Out
First, turn your steering wheel left and right. That will
clear the area around your front wheels. Shift the
transfer case into 4HI. Then shift back and forth
between REVERSE (R) and a forward gear, spinning the
wheels as little as possible. Release the accelerator pedal
while you shift, and press lightly on the accelerator
pedal when the transmission is in gear. By slowly
spinning your wheels in the forward and reverse
directions, you will cause a rocking motion that may
free your vehicle. If that doesn't get you out after a few
tries, you may need to be towed out. Or, you can use
your recovery hooks if your vehicle has them. If you do
need to be towed out, see ªTowing Your Vehicleº in
the Index.
Using the Recovery Hooks
Your vehicle is equipped with recovery hooks. The
recovery hooks are provided at the front of your vehicle.
You may need to use them if you're stuck off
-road and
need to be pulled to some place where you can
continue driving.

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6-21 What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. See ªRecommended Fluids and
Lubricantsº in the Index.
Four-Wheel Drive
Transfer Case
When to Check Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant. See ªPeriodic Maintenance
Inspectionsº in the Index.How to Check Lubricant
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.
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. See ªRecommended Fluids and
Lubricantsº in the Index.

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6-58
Fuse/Circuit
BreakerUsage
1 Stop/TCC Switch, Buzzer, CHMSL,
Hazard Lamps, Stoplamps
2 Transfer Case
3 Courtesy Lamps, Cargo Lamp, Glove
Box Lamp, Dome/Reading Lamps,
Vanity Mirrors, Power MirrorsFuse/Circuit
BreakerUsage
4 Instrument Cluster, DRL Relay, Lamp
Switch, Keyless Entry, Low Coolant
Module, Illuminated Entry Module
5 Rear Comfort Controls
6 Cruise Control
7 Auxiliary Power Outlet
8 Crank
9 License Lamp, Parking Lamps,
Taillamps, Tailgate Lamps, Front
Sidemarkers, Fog Lamp Relay, Door
Switch Illumination, Fender Lamps,
Headlamp Switch Illumination
10 Air Bag System
11 Wiper Motor, Washer Pump
12 A/C, A/C Blower, High Blower Relay
13 Power Amp, Rear Liftglass, Cigarette
Lighter, Door Lock Relay, Power
Lumbar Seat
14 4WD Indicator, Cluster, Front and Rear
Comfort Controls, Instrument Switches,
Radio Illumination, Chime Module

Short Trip/City Scheduled Maintenance
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7-7
The services shown in this schedule up to 100,000 miles
(166 000 km) should be performed after 100,000 miles
(166 000 km) at the same intervals. The services shown
at 150,000 miles (240 000 km) should be performed at
the same interval after 150,000 miles (240 000 km).
See ªOwner Checks and Servicesº and ªPeriodic
Maintenance Inspectionsº following.
Footnotes
 The U.S. Environmental Protection Agency or the
California Air Resources Board has determined that the
failure to perform this maintenance item will not nullify
the emission warranty or limit recall liability prior to the
completion of the vehicle's useful life. We, however, urge
that all recommended maintenance services be performed
at the indicated intervals and the maintenance be recorded.
# Lubricate the front suspension, kingpin bushings,
steering linkage, transmission shift linkage, transfer case
shift linkage, parking brake cable guides, front axle
propshaft spline and brake pedal springs. Ball joints and
kingpin bushings should not be lubricated unless their
temperature is 10F (
-12C) or higher, or they could
be damaged.+ A good time to check your brakes is during tire
rotation. See ªBrake System Inspectionº under ªPeriodic
Maintenance Inspectionsº in Part C of this schedule.
** Drive axle service (see ªRecommended Fluids and
Lubricantsº in the Index for proper lubricant to use):

Locking Differential
-- Drain fluid and refill at first
engine oil change. At subsequent oil changes, check
fluid level and add fluid as needed. If driving in
dusty areas or towing a trailer, drain fluid and refill
every 15,000 miles (25 000 km).

More frequent lubrication may be required for
heavy
-duty or off-road use.

Long Trip/Highway Scheduled Maintenance
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7-25
The services shown in this schedule up to 100,000 miles
(166 000 km) should be performed after 100,000 miles
(166 000 km) at the same intervals. The services shown
at 150,000 miles (240 000 km) should be performed at
the same interval after 150,000 miles (240 000 km).
See ªOwner Checks and Servicesº and ªPeriodic
Maintenance Inspectionsº following.
Footnotes
 The U.S. Environmental Protection Agency or the
California Air Resources Board has determined that the
failure to perform this maintenance item will not nullify
the emission warranty or limit recall liability prior to the
completion of the vehicle's useful life. We, however,
urge that all recommended maintenance services be
performed at the indicated intervals and the maintenance
be recorded.# Lubricate the front suspension, kingpin bushings,
steering linkage, transmission shift linkage, transfer case
shift linkage, parking brake cable guides, front axle
propshaft spline and brake pedal springs. Ball joints and
kingpin bushings should not be lubricated unless their
temperature is 10F (
-12C) or higher, or they
could be damaged.
+ A good time to check your brakes is during tire
rotation. See ªBrake System Inspectionº under ªPeriodic
Maintenance Inspectionsº in Part C of this schedule.
** Drive axle service (see ªRecommended Fluids and
Lubricantsº in the Index for proper lubricant to use):

Locking Differential
-- Drain fluid and refill at first
engine oil change. At subsequent oil changes, check
fluid level and add fluid as needed.

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7-40 Drive Axle Service
Check rear/front axle fluid level and add as needed.
Check constant velocity joints and axle seals for leaking.
Transfer Case (Four-Wheel Drive)
Inspection
Every 12 months or at oil change intervals, check front
axle and transfer case and add lubricant when necessary.
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. Also inspect drum brake linings
for wear and cracks. Inspect other brake parts, including
drums, wheel cylinders, calipers, parking brake, etc.
Check parking brake adjustment. You may need to have
your brakes inspected more often if your driving habits
or conditions result in frequent braking.

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USAGEFLUID/LUBRICANT
Front AxleSAE 80W-90 Axle Lubricant (GM
Part No. 1052271 or equivalent).
Rear Axle
(Locking
Differential)SAE 80W-90 Axle Lubricant;
use only GM Part No. 1052271.
Do not add friction modifier.
Automatic
Transfer CaseAutomatic Transfer Case Fluid
(GM Part No. 12378396).
Front Axle
Propshaft Spline
and Universal
JointsChassis Lubricant (GM Part
No. 12377985 or equivalent) or
lubricant meeting requirements of
NLGI # 2, Category LB
or GC
-LB.
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.
USAGEFLUID/LUBRICANT
Hood and Door
HingesMulti-Purpose Lubricant,
Superlube
(GM Part
No. 12346241 or equivalent).
Body Door
Hinge Pins,
Tailgate Hinge
and Linkage,
Folding Seat and
Fuel Door HingeMulti-Purpose Lubricant,
Superlube
(GM Part
No. 12346241 or equivalent).
Outer Tailgate
Handle Pivot
PointsMulti-Purpose Lubricant,
Superlube
(GM Part
No. 12346241 or equivalent).
Weatherstrip
ConditioningDielectric Silicone Grease (GM
Part No. 12345579 or equivalent).
Weatherstrip
SqueaksSynthetic Grease with Teflon,
Superlube
(GM Part
No. 12371287 or equivalent).

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CURRENT PUBLICATIONS FOR 1999 GMC
SERVICE MANUALS
Service Manuals have the diagnosis and repair information
on engines, transmission, axle, suspension, brakes,
electrical, steering, body, etc.
RETAIL SELL PRICE: $90.00
TRANSMISSION, TRANSAXLE, TRANSFER CASE
UNIT REPAIR MANUAL
This manual provides information on unit repair service
procedures, adjustments and specifications for the
1999 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 directly 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: $15.00
Without Portfolio: Owner's Manual only.
RETAIL SELL PRICE: $10.00
CURRENT & 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.
PLEASE COMPLETE THE ORDER FORM SHOWN ON
THE FOLLOWING PAGE AND MAIL TO:
Helm, Incorporated
P.O. Box 07130
Detroit, MI 48207OR ORDER TOLL FREE: 1-800-551-4123
Monday-Friday 8:00 AM ± 6:00 PM Eastern Time
For Credit Card Orders Only (VISA±MasterCard±Discover)
1999 GMC SERVICE PUBLICATIONS ORDERING INFORMATION
The following publications covering the operation and servicing of your vehicle can be purchased by filling out
the Service Publication Order Form in this book and mailing it in with your check, money order,
or credit card information to Helm, Incorporated (address below.)