MAINTENANCE OF THE M113 PER CARRIER - OD1601 LESSON 1/TASK 1
(1) Engine. Power is supplied by a liquid cooled 6-cylinder, V-type compression-
ignition (diesel) engine. Starting is by a 24-volt heavy duty electrical cranking
motor.
During operation, the engine is safeguarded by transmitters and warning
light circuits in the oil and cooling systems.
(2) Transfer Gearcase. The transfer gearcase bolts to the rear (output end) of
the engine and to the front (input end) of the transmission. Power is transferred
from the engine to the transmission by the transfer gearcase. An engine disconnect
in the transfer gearcase allows the engine to operate independently of the rest of
the powertrain (the generator continues to operate).
A power takeoff drives the
differential oil pump.
A second power takeoff drives the cooling fan through a
pulley and drive-belts.
A third power takeoff drives the generator through a
pulley and drive-belts.
(3) Transmission. The transmission bolts to the transfer gearcase with the input
end toward the rear of the carrier.
The transmission consists of a hydraulic
torque converter with lockup clutch and basic three-speed constant mesh planetary
gear train. In each range, the transmission starts in first gear converter (except
in 2-3 range) followed by an automatic shift into lockup. Then, depending on the
range selected, the transmission upshifts automatically and sequentially to the top
gear in that range.
Downshifting, in descending order, is also automatic as the
carrier speed decreases.
All shifts are throttle modulated so transmission
upshifting and downshifting are consistent with the engine operating range and
driver's performance requirements.
During operation, the transmission is
safeguarded by a transmitter and warning light circuit in the oil system.
(4) Steering Control Differential (Brake). The steering control differential is
a double planetary geared unit, controlled by drag exerted on the internal brake
drums.
A single input shaft connects the differential to the transmission, and
left and right output shafts connect the differential to the final drives.
The
differential consists of five major assemblies: the right-angle gearbox, steering
unit, steering brake shoes, and output shafts.
Power from the transmission is
transmitted through the right-angle gearbox to the steering unit in the center
housing. The steering
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