OPERATOR'S MANUAL
Table Of Contents
- How to Use This Manual
- Safety Signals
- Vehicle Safety
- How to Find What You Want
- A Special Word About Repairs
- Shop Manuals
- Preventive Maintenance Section
- Additional Sources of Information
- Start–Up
- Instruments and Controls
- Introduction
- Warning Lights and Buzzer
- Self Test
- Speedometer and Odometer
- Tachometer
- Coolant (Water) Temperature Gauge
- Engine Oil Pressure Gauge
- Dual Air Pressure Gauge (Air Reservoir)
- Fuel Gauge
- Voltmeter (option)
- Transmission Temperature Gauge (option)
- Air Filter Restriction Indicator (option)
- Headlight Switch
- Daytime Running Lights (option)
- Panel Lights
- ID and Clearance Lights
- Windshield Wipers/Washer
- Ignition Key Switch
- Parking Brake
- Cruise Control Switch
- Hand Throttle Control
- Heating and Air Conditioning
- Accessories
- Seats
- Steering Column and Mirrors
- Operating the Engine
- Operating the Transmission
- Using the Brake System
- Operating the Rear/Drive Axle
- More Driving Tips and Techniques
- Vehicle Recovery and Spring Brakes
- Shut–Down
- Introduction
- Maintenance Schedule and Lubrication
- Engine Maintenance
- Cooling System
- Brake System
- Air System
- Tires and Wheels
- Heater and Air Conditioner
- Electrical System
- Cab Maintenance
- Transmission and Clutch
- Steering and Driveline
- Front Axle and Suspension
- Rear Axle and Suspension
- Frame and Fifth Wheel
- Noise and Emission Control
- Consumer Information and Vehicle Identification
Operating the Rear/Drive Axle Operating Instructions
– 94 –
PB1318 3/01 Model 330
In the LOCK position, an air operated clutch positively locks
both sets of axles together, providing greater traction on slip-
pery road surfaces; however, steering around corners and on
dry pavement is more difficult. Continuous operation on a
paved, dry surface stresses the tandem axles, possibly caus-
ing internal damage.
Use this feature only when driving on surfaces with poor trac-
tion, such as wet slippery roads, heavy mud or snow, or loose
gravel. And do not use it when going downhill or at speeds
greater than 25 mph (40 km/h).
Lock the
inter-axle differential when you encounter road con-
ditions such as these:
• Ice or snow — with or without tire chains.
• Dirt roads.
• Loose sand, mud, or other rough road conditions.
WARNING! Do not put the differential lock in the
LOCK position while the wheels are spinning
freely (slipping), you could lose control of the
vehicle or cause axle damage—you could be
injured. Switch to LOCK only when the wheels
are not spinning.
• Look ahead for wet, muddy, or icy patches on the road,
stop your vehicle and switch to LOCK ahead of time.
WARNING! Do not operate the vehicle on dry
pavement with the differential locked. This could
lead to an injury accident. On dry pavement, you
will not be able to steer well with the differential
locked. Lock the differential only when operating
on surfaces with poor traction, such as wet, slip-
pery roads or loose gravel.
Inter–Axle Differential Lock Operation
WARNING! Do not use the inter-axle differential
lock when travelling downhill or at speeds above
25 mph (40 km/h). When it is engaged under
these conditions, your vehicle will exhibit
“understeer” handling characteristics. This
“understeer” condition will cause your vehicle
to turn less quickly and more steering effort will
be required, which can cause an injury accident.
To LOCK the inter-axle differential:
1. Anticipate when you might need increased traction, slow
down to a steady speed under 25 mph (40 km/h) or stop
the vehicle. Do not lock the inter-axle differential while










