TM 9-2320-365-34-1
1-10. POWERTRAIN (CONT)
Figure 1-5. Powertrain (Cont)
a. Engine. The vehicle is equipped with a Caterpillar diesel engine, model 3116 ATAAC (Air-to Air After Cooler) (1,
Figure 1-5), rated at 225 HP.
b. Transmission. The vehicle is equipped with an Allison automatic transmission, model MD3070PT (2, Figure 1-5).
It is a fully automatic electronically controlled seven-speed close-ratio transmission.
(1) The TEPSS contains microprocessor based electronics, and is located in the instrument panel to the driver’s left.
The TPSS is located in the instrument panel to the driver’s left, while the transmission ECU is located behind the kick
panel. The ECU receives information, in the form of electrical signals from the various sensors, processes that
information, then sends the appropriate signals to the solenoids which control transmission function. The ECU
incorporates a diagnostic program which enables it to identify numerous actual and/or potential transmission
problems. The TEPSS and TPSS are capable of displaying diagnostic codes in the Light Emitting Diode (LED)
display on the pushbutton shift selector. These diagnostic codes are stored in the ECU for later retrieval. The
pushbutton shift selector is used for selecting transmission range. The transmission defaults to Neutral (N) whenever
electrical power is removed from the vehicle. The Drive (D) gear selection is used for normal driving conditions. The
transmission will engage 2nd gear when D is selected and the vehicle is stopped. As the accelerator is depressed
and speed increases, the transmission will automatically upshift through 3rd, 4th, 5th, 6th, and 7th gears. Low gear
(1st gear), is available only by manual selection. Selecting a specific gear; for example, 3rd; will prevent the
transmission upshifting past the selected gear. This is useful if road or load conditions require lower gear range
operation. When road conditions improve or load is reduced, the shift selector can be returned to the normal (D)
driving position. When electrical power is applied to the TEPSS and a fault is detected in the transmission controls,
the TEPSS will emit an eight second series of beeps. When electrical power is applied to the TPSS and a fault is
detected in the transmission controls, "--" will appear in the TPSS LED display. In either case, the transmission will
not engage a range (forward or reverse) when D or Reverse (R) range is selected on the pushbutton shift selector.
TM 9-2320-365-10 provides full operating instructions for the transmission.
(2) The transmission may include a Power Take-Off (PTO). The PTO powers a hydraulic pump which supplies
hydraulic pressure for an 11K self-recovery winch (SRW).
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