TM 9-2320-272-24-2
CHAPTER 4
DIRECT SUPPORT (DS) MAINTENANCE
Direct. Support (DS) and General Support (GS)
Section I.
Mechanical Troubleshooting (page 4-1)
Power Plant Maintenance (page 4-35)
Section II.
Engine Maintenance (M939/A1) (page 4-117)
Section III.
Engine Maintenance (M939A2) (page 4-271)
Section IV.
Cooling System Maintenance (page 4-352)
Section V.
Electrical System Maintenance (page 4-388)
Section VI.
Transmission Maintenance (page 4-465)
Section VII.
Transfer Case Maintenance (page 4-504)
Section VIII.
Front and Rear Axle Maintenance (page 4-548)
Section IX.
Compressed Air and Brake System Maintenance (page 4-584)
Section X.
Power Steering System Maintenance (page 4-605)
Section XI.
Frame Maintenance (page 4-680)
Section XII.
Body, Cab, and Hood Maintenance (page 4-691)
Section XIII.
Special Purpose Bodies Maintenance (page 4-715)
Section XIV.
Winch, Hoist, and Power Takeoff Maintenance (page 4-808)
Section XV.
Special Purpose Kits Maintenance (page 4-1002)
Section XVI.
4-1. GENERAL
This section provides troubleshooting and maintenance instructions for maintaining M939, M939A1, and
M939A2 series vehicles at the Direct Support (DS) maintenance level. A description of the differences
between models can be found in chapter 1 of TM 9-2320-272-24-1. Procedures found in this chapter pertain
to all models within a vehicle series unless otherwise designated.
Section I. DIRECT SUPPORT (DS) AND
GENERAL SUPPORT (GS) MECHANICAL TROUBLESHOOTING
4-2. SCOPE
a. This section provides diagnostic and corrective procedures for the mechanical system at the Direct
Support (DS) maintenance level. These procedures cannot give all the answers or correct all vehicle
malfunctions encountered. However, these procedures are an organized step-by-step approach to a problem
that will direct tests and inspections toward the source of a problem and successful solution.
Information in this section is for use in conjunction with, and as a supplement to, troubleshooting
procedures found in TM 9-2320-272-24-1.
b. Do the easiest things first. Most problems are easily corrected.
c. Doublecheck before disassembly. The source of most problems can be traced to more than one part
in a system.
d. Before attempting to correct a problem, diagnose the cause of the problem. Do not allow the same
failure to occur again.
Troubleshooting.
4-1
