ITM 55-1660-320-23 & P
j. Overhaul. That maintenance effort (service / action) prescribed to restore an item to a completely serviceable /
operational condition as required by maintenance standards in appropriate technical publications (i.e., DMWR), Overhaul
is normally the highest degree of maintenance performed by the Army. Overhaul does not normally return an item to
like-new condition.
k. 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 (hours /
miles, etc.) considered in classifying Army equipment / components.
B-4. Functional Groups (Columns 1 and 2.) The functional groupings shown in the sample below identify
maintenance significant components, assemblies, subassemblies and modules with the next higher assembly.
GROUP
GROUP
NUMBER
DESCRIPTION
NUMBER
DESCRIPTION
04
AUXILIARY POWER UNIT
0401
ENGINE GENERAL
Servicing, handling,
inspection requirements,
lubrication charts, overhaul
and retirement schedules.
External lines and hoses.
(As applicable)
0402
COMBUSTION SECTION
Liners, nozzles, stators,
rotor, seals, couplings,
blades and housing.
0403
POWER-TURBINE (POWER
TURBINE MODULE)
Nozzles, rotors, blades,
exit guide vanes, exhaust
frame, drive shaft, bearings,
seals, external lines and
hoses.
0404
FUEL SYSTEM
Fuel control, fuel boost pump,
governors, fuel filter
assembly, sequence valve, fuel
manifold, fuel nozzle,
external lines and hoses.
0405
ELECTRICAL SYSTEM
Electrical control units,
exciters, thermocouples,
ignition harness, electrical
cables, history record, torque
overspeed sensor, Np sensor,
alternate stator, blowers.
0406
OIL SYSTEM
Tanks, oil filter, oil cooler,
lube and scavenge pumps, oil
filter bypass sensor, external
lines and hoses.
0407
DRIVE SYSTEM
Reduction gear assembly, output
shaft, seal, bearing.
0408
MISCELLANEOUS EQUIPMENT
(As applicable).
B-4
