TM-9-2320-272-23-5
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; FIELD MAINTENANCE MANUAL; VOLUME 5 OF 5
SEPTEMBER 2012
TM-9-2320-272-23-5 - Page 458 of 623
MAINTENANCE ALLOCATION CHART (MAC) INTRODUCTION
- Continued
is normally the highest degree of maintenance performed by the Army. Overhaul does not normally return
an item to like new condition.
12. Rebuild. Consists of those services/actions necessary for the restoration of unserviceable equipment to a
like new condition in accordance with original manufacturing standards. Rebuild is the highest degree of
material maintenance applied to Army equipment. The rebuild operation includes the act of returning to zero
those age measurements (e.g., hours/miles) considered in classifying Army equipment/components.
Explanation of Columns in the MAC
Column (1) Group Number. Column (1) lists Functional Group Code (FGC) numbers, the purpose of which is to
identify maintenance significant components, assemblies, subassemblies, and modules with the Next Higher
Assembly (NHA).
Column (2) Component/Assembly. Column (2) contains the item names of components, assemblies, subassemblies,
and modules for which maintenance is authorized.
Column (3) Maintenance Function. Column (3) lists the functions to be performed on the item listed in column (2).
(For a detailed explanation of these functions refer to "Maintenance Functions" outlined above).
Column (4) Maintenance Level. Column (4) specifies each level of maintenance authorized to perform each function
listed in column (3), by indicating work time required (expressed as manhours in whole hours or decimals) in the
appropriate subcolumn. This work time figure represents the active time required to perform that maintenance
function at the indicated level of maintenance. If the number or complexity of the tasks within the listed maintenance
function varies at different maintenance levels, appropriate work time figures are to be shown for each level. The
work time figure represents the average time required to restore an item (assembly, subassembly, component,
module, end item, or system) to a serviceable condition under typical field operating conditions. This time includes
preparation time (including any necessary disassembly/assembly time), troubleshooting/fault location time, and
quality assurance time in addition to the time required to perform the specific tasks identified for the maintenance
functions authorized in the MAC. The symbol designations for the various maintenance levels are as follows:
Field :
C Crew maintenance
F Maintainer maintenance
Sustainment :
L Specialized Repair Activity (SRA)
H Below depot maintenance
D Depot maintenance
NOTE
The "L" maintenance level is not included in column (4) of the MAC. Functions to this level
of maintenance are identified by work time figure in the "H" column of column (4), and an
associated reference code is used in the REMARKS column (6). This code is keyed to the
remarks and the SRA complete repair application is explained there.
Column (5) Tools and Equipment Reference Code. Column (5) specifies, by code, those common tool sets (not
individual tools), common Test, Measurement and Diagnostic Equipment (TMDE), and special tools, special TMDE
and special support equipment required to perform the designated function. Codes are keyed to the entries in the
tools and test equipment table.
Column (6) Remarks Code. When applicable, this column contains a letter code, in alphabetical order, which is keyed
to the remarks table entries.
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