Section III. PRINCIPLES OF OPERATION
This section explains how components of the 5-ton M939/A1/A2 series vehicles work together. A functional
description of these components and their related parts will be covered in the following paragraphs. To find the operation
of a specific system or component, see the principles of operation reference index below.
PRINCIPLES OF OPERATION REFERENCE INDEX
Control System Operation
Power System Operation
Electrical Systems Operation
Compressed Air and Brake System Operation
Hydraulic System Operation
CONTROL SYSTEM OPERATION
The control system includes those controls and their related parts that are essential to the operation of the vehicle.
These controls are common to all vehicles with the exception of the transmission and transfer case power takeoff controls.
All originate from the cab. Each of these controls and their related parts will be described as part of the following systems:
Starting and Ether Starting System Operation (page 1-28).
Accelerator Controls System Operation (page 1-30).
Parking Brake System Operation (page 1-31).
Steering System Operation (page 1-32).
Transmission Control System Operation (page 1-33).
Transfer Case Control System Operation (page 1-34).