trailer GMC SIERRA 2001 Workshop Manual

6-25
Automatic Transmission Fluid
(Allison Only)
When to Check and Change
A good time to check your automatic transmission fluid
level is when the engine oil is changed.
Change both the fluid and filter every 25,000 miles
(41 500 km) if the vehicle is mainly driven under one
or more of these conditions:

In heavy city traffic where the outside temperature
regularly reaches 90F (32C) 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 every 50,000 miles (83 000 km).
See ªScheduled Maintenance Servicesº in the Index.
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 fluid can damage your
transmission. Too much can mean that some of
the fluid could come out and fall on hot engine
parts or exhaust system parts, starting a fire.
Be sure to get an accurate reading if you check
your transmission fluid.
Wait at least 30 minutes before checking the
transmission fluid level if you have been driving:

When outside temperatures are above 90F (32C).

At high speed for quite a while.

In heavy traffic
-- especially in hot weather.

While pulling a trailer.

6-30
Hydraulic Clutch
The hydraulic clutch linkage in your vehicle is
self
-adjusting. The clutch master cylinder reservoir is
filled with hydraulic clutch fluid.
It is not necessary to regularly check clutch fluid unless
you suspect there is a leak in the system. Adding fluid
won't correct a leak.
A fluid loss in this system could indicate a problem.
Have the system inspected and repaired.
When to Check and What to Use
Refer to the Maintenance
Schedule to determine how
often you should check the
fluid level in your clutch
master cylinder reservoir
and for the proper fluid.
See ªOwner Checks
and Servicesº and
ªRecommended Fluids and
Lubricantsº in the Index.
How to Check and Add Fluid
The proper fluid should be added if the level does not
reach the bottom of the diaphragm when it's in place in
the reservoir. See the instructions on the reservoir cap.
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 for
more information.

6-74
Center Instrument Panel Utility Block
The center instrument panel utility block is located
underneath the instrument panel, to the left of the
steering column.
Name Usage
SEO Special Equipment Option
HTD ST Heated Seats
SPARE 4 Not UsedName Usage
VANITY Headliner Wiring
TRAILER Trailer Brake Wiring
PWR ST Power Seats
SPARE 5 Not Used
CLUTCH Manual Transmission Clutch Switch
UPF Upfitter
PARK LAMP Parking Lamps (Relay)
FRT PRK EXPT Not Used (Fuse)
SL RIDE Manual Selectable Ride Switch
SPARE 2 Not Used
RR PRK LP Not Used (Relay)
RR FOG LP Not Used (Relay)
SPARE 3 Not Used
INADV PWR Interior Lights Feed
CTSY LP Courtesy Lamps
CEL PHONE Cellular Telephone Wiring

6-77
*1 INJ B--Gasoline Engine and Diesel Engine.
*2 ECM I
--Gasoline Engine; ECMRPV--Diesel Engine.
*3 02 A
--Gasoline Engine; FUEL HT--Diesel Engine.
*4 02 B
--Gasoline Engine; ECM I--Diesel Engine.
Name Usage
GLOW PLUG Diesel Glow Plugs and
Intake Air Heater
CUST FEED Gasoline Accessory Power
STUD #1Accessory Power/Trailer
Wiring Feed
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 Not Used
STUD #2 Accessory Power/Trailer Wiring
Brake Feed
SPARE Spare FuseName Usage
TRL R TRN Right Turn Signal Trailer Wiring
TRL L TRN Left Turn Signal Trailer Wiring
IGN 1 Ignition, Fuel Controls (Relay)
INJ B Ignition, Fuel Controls
STARTER Starter (Relay)
PARK LP Parking Lamps
FRT HVAC Climate Control System
STOP LP Exterior Lamps, Stoplamps
ECM I PCM
ECMRPV Fuel Controls, ECM
CHMSL Center High Mounted Stoplamp
VEH STOP Stoplamps, Cruise Control
TRL B/U Backup Lamps Trailer Wiring
INJ A Fuel Controls, Ignition
RR HVAC Not Used
VEH B/U Vehicle Backup Lamps
ENG 1 Engine Controls, Canister Purge,
Fuel System

6-78
Name Usage
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
RR DEFOG Rear Window Defogger,
Heated Mirrors (Relay)
RR PRK Right Rear Parking Lamps
ECM B PCM
F/PMP Fuel Pump (Relay)
O2 A Oxygen Sensors
FUEL HT Fuel Heater, Glow Plug and
Intake Heater Controls
O2 B Oxygen Sensors
LR PRK Left Rear Parking Lamps
RR DEFOG Rear Window Defogger,
Heated MirrorsName Usage
HDLP Headlamps (Relay)
TRL PRK Parking Lamps Trailer Wiring
RT HDLP Right Headlamps
DRL Daytime Running Lamps (Relay)
HTD MIR Heated Mirrors
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

Scheduled Maintenance -- Gasoline Engines
7-9
7,500 Miles (12 500 km)

Drive axle service. If your vehicle is used to pull a trailer, a rear axle fluid
change is recommended after a break
-in period. Change the rear axle fluid
after the first 500 miles (800 km) of trailer towing. See ªRecommended Fluids
and Lubricantsº in the Index for the proper fluid to use.

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 +.)
15,000 Miles (25 000 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 +.)
ACTUAL
SERVICED BY:MILEAGE
DATE
ACTUAL
SERVICED BY:MILEAGE
DATE

Scheduled Maintenance -- Gasoline Engines
7-10
22,500 Miles (37 500 km)

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 +.)
25,000 Miles (41 500 km)

Allison Transmission Only: Change automatic transmission fluid and filters
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 every 50,000 miles (83 000 km).
ACTUAL
SERVICED BY:MILEAGE
DATE
ACTUAL
SERVICED BY:MILEAGE
DATE

Scheduled Maintenance -- Gasoline Engines
7-12
50,000 Miles (83 000 km)

Except Allison Transmission: 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.
Except Allison Transmission: If you do not use your vehicle under any of
these conditions, change the fluid and filter at 100,000 miles (166 000 km).
Allison Transmission Only: If you haven't used your vehicle under severe
conditions listed previously and, therefore, haven't changed your automatic
transmission fluid, change both the fluid and filter.
Automatic Transfer Case Only: Change transfer case fluid.
52,500 Miles (87 500 km)
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 +.)
ACTUAL
SERVICED BY:MILEAGE
DATE
ACTUAL
SERVICED BY:MILEAGE
DATE

Scheduled Maintenance -- Gasoline Engines
7-14
67,500 Miles (112 500 km)

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 +.)
75,000 Miles (125 000 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.

Allison Transmission Only: Change automatic transmission fluid and filter
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 every 50,000 miles (83 000 km).
Rotate tires. See ªTire Inspection and Rotationº in the Index for proper
rotation pattern and additional information. (See footnote +.)
ACTUAL
SERVICED BY:MILEAGE
DATE
ACTUAL
SERVICED BY:MILEAGE
DATE

Scheduled Maintenance -- Gasoline Engines
7-16
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.
Automatic Transfer Case Only: Change transfer case fluid.
Inspect Positive Crankcase Ventilation (PCV) valve.
An Emission Control Service. ACTUAL
SERVICED BY:MILEAGE
DATE