Allison Automatic Transmission Driving Tips - Blue Bird D3RE 2014 Driver's Handbook Manual

Allison Automatic Transmission Driving Tips

Accelerator Control
The pressure of your foot on the accelerator pedal influences the automatic shift-
ing. An electronic signal tells the ECU how far the driver has depressed the pedal.
This provides the accurate shift spacing and control necessary for maximum perfor-
mance.
Downshift or Reverse Inhibitor Feature with Allison 3000 PTS Transmission
Although there is no limitation on upshifting, there is a limit on downshifting and
shifts from neutral into drive or reverse. If a downshift or neutral-to-range shift is
selected when the engine speed or throttle position is too high, the ECU/TCM will
not allow the shift until reaching a lower speed. If idle speed is too high, shifts to
range are prohibited. A continuous "beep" tone sounds when reverse is selected dur-
ing forward movement or if a neutral-to-range shift is selected at too high an engine
speed.
Cold Weather Starts
Most Allison transmissions are programmed to restrict operation until operating
temperature is reached. When the transmission fluid temperature is below -25°
F (-32° C), the transmission will not shift into an operating range and the "Check
Transmission" light will be illuminated. When the transmission fluid temperature is
between -24° F and 20° F (-31° C to -7° C), the transmission will operate in 1st, 2nd,
or Reverse only. If there is no other problem with the transmission, the "Check Trans-
mission" light will not be illuminated. For transmission fluid temperatures above 20°
F (-7° C), the transmission will shift and operate in a normal manner. Be sure to read
and understand the cold weather operation instructions in the Allison Transmission™
Operator's Manual supplied with the bus.
Using the Engine to Slow the Vehicle
To use the engine as a braking force, shift the range selector to the next lower
range. If the vehicle is exceeding the maximum speed for a lower gear, use the ser-
vice brakes to slow the vehicle to an acceptable speed where the transmission may
be downshifted safely. After reaching the lower speed, the ECU will automatically
downshift the transmission. Engine braking provides good speed control for going
down grades. When the vehicle is heavily loaded, or the grade is steep, it may be de-
sirable to select a lower range before reaching the grade. If engine-governed speed
is exceeded, the transmission will upshift automatically to the next range.
[CAUTION] The transmission incorporates a hold feature to prohibit upshift-
ing above the range selected during normal driving. For downhill operation,
select a lower transmission range. However, if engine governed speed is ex-
ceeded, the transmission may upshift to the next higher range. Use the vehicle
service brakes to prevent exceeding engine governed speed in the held range.
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DRIVER'S HANDBOOK