2001 CHEVROLET TAHOE transfer case

6-25
Rear Axle
When to Check Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant. Additional rear axle
scheduled maintenance is required when trailer towing.
See ªScheduled Maintenance Servicesº in the Index.
How to Check Lubricant
1500 Series shown, 2500 and 3500 Series similarThe proper level for the 1500 Series is from 5/8 inch to
1 5/8 inch (15 mm to 40 mm) below the filler plug.
The proper level for the 2500 Series is from 0 to 3/8 inch
(0 to 10 mm) below the filler plug. Add only enough fluid
to reach the proper level.
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
Most lubricant checks in this section also apply to
four
-wheel-drive vehicles. However, they have
two additional systems that need lubrication.
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.

6-26
How to Check Lubricant
Automatic Transfer Case
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 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.
How to Check Lubricant
If the level is below the bottom of the filler plug hole,
you may need to add some lubricant.

6-69
Name Usage
STUD #1 Accessory Power/Trailer Wiring
Feed/Load Leveling
ABS Anti
-Lock Brakes
IGN A Ignition Switch
AIR A.I.R. System
RAP #1 Retained Accessory Power,
Power Mirrors, Power Door Locks,
Power Seat(s)
IGN B Ignition Switch
RAP #2 Retained Accessory Power/Rear
Power Windows, Sunroof, Radio
STUD #2 Accessory Power/Trailer Wiring
Brake Feed
TRL R TRN Right Turn Signal Trailer Wiring
TRL L TRN Left Turn Signal Trailer Wiring
IGN 1 Ignition, Fuel Controls
INJ B Ignition, Fuel Controls (Relay)
STARTER Starter (Relay)
PARK LP Parking LampsName Usage
FRT HVAC Climate Control System
STOP LP Exterior Lamps, Stoplamps
ECM I PCM
CHMSL Center High Mounted Stoplamp
VEH STOP Stoplamps, Cruise Control
TRL B/U Backup Lamps Trailer Wiring
INJ A Fuel Controls, Ignition
RR HVAC Rear HVAC
VEH B/U Vehicle Backup Lamps
ENG 1 Engine Controls, Canister Purge,
Fuel System
ETC Electronic Throttle Control
IGN E A/C Compressor Relay, Rear
Window Defogger, Daytime
Running Lamps, A.I.R. System
B/U LP Backup Lamps, Automatic
Transmission Shift Lock
Control System
ATC Automatic Transfer Case

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. The system
will show you when to change the oil
-- usually between
3,000 miles (5 000 km) and 10,000 miles (16 000 km)
since your last oil change. Under severe conditions, the
indicator may come on before 3,000 miles (5 000 km).
Never drive your vehicle more than 10,000 miles
(16 000 km) or 12 months without an oil and
filter change.
The system won't detect dust in the oil. So if you drive
in a dusty area, be sure to change your oil and filter
every 3,000 miles (5 000 km) or sooner if the CHANGE
ENGINE OIL message appears. Remember to reset
the Oil Life System when the oil and filter have been
changed. See ªOil Life Systemº in the Index for
information on resetting.
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, parking brake cable guides, and brake front
axle. 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 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 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.
Inspect Positive Crankcase Ventilation (PCV) valve.
An Emission Control Service. ACTUAL
SERVICED BY:MILEAGE
DATE

7-23 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
Key
Lock CylindersMulti-Purpose Lubricant,
Superlube
(GM Part
No. 12346241 or equivalent).
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).
USAGEFLUID/LUBRICANT
Rear AxleSAE 75W-90 Synthetic Axle
Lubricant (GM Part No. 12378261)
or equivalent meeting GM
Specification 9986115.
Automatic
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.