Section III. PRINCIPLES OF OPERATION

TM 9-2320-364-34-1

1-8. LOCATION AND DESCRIPTION OF MAJOR COMPONENTS.

Refer to TM 9-2320-364-10 for location and description of major components.

1-9. EQUIPMENT DATA.

Refer to TM 9-2320-364-10 for equipment data.

Section III. PRINCIPLES OF OPERATION

1-10. POWER TRAIN.

Figure 1-5. Power Train

Power for the truck is provided by a diesel engine (1) (Figure 1-5) which is coupled directly to an automatic

transmission (2). Power from the transmission is transferred to the transfer case (3) and on to the drive and steering

axles (4) and the drive only axles (5) through a series of drive shafts and universal joints. The truck drive train is

enhanced through the use of the Detroit Diesel Electronic Control II (DDEC II) or Detroit Diesel Electronic Control

III/IV (DDEC III/IV) electronic engine controller and the Allison Transmission Electronic Control (ATEC) electronic

transmission controller. The primary components of the ATEC system are an Electronic Control Unit (ECU) and

shifter in the truck cab, an electrohydraulic valve module beneath the transmission gearing section that contains

solenoid valves for clutch control, a throttle sensor that is activated by the accelerator pedal and an output speed

sensor that relays the transmission out put speed to the ECU for shifting and control functions.

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