freightliner M2 Plus 2023 Manual page 179

1. Current Gear
2. Highest Gear
Available
Fig. 14.12, Allison Gear Display in Automatic Mode
NOTICE
The engine should never be operated for more
than thirty seconds at full throttle with the
transmission in gear and the output stalled.
Prolonged operation of this type will overheat the
transmission fluid and will result in severe
damage to the transmission.
NOTICE
Do not allow the vehicle to coast in neutral. This
can result in severe transmission damage. Also,
no engine braking is available.
The following tips highlight important operation
principles.
•
Use reverse (R) to back the vehicle.
Completely stop the vehicle before shifting
from a forward gear to reverse, or from reverse
to forward.
•
Select drive (D) for all normal driving
conditions. The vehicle will start out in 1st gear
(unless the transmission is programmed with
2nd gear start), and as speed increases, the
transmission will upshift through each gear
automatically. As the vehicle slows down, the
transmission will downshift to the correct gear
automatically.
•
The pressure of your foot on the accelerator
pedal influences the automatic shifting. When
the pedal is fully depressed, the transmission
will automatically upshift at higher engine
speeds. A partially-depressed position of the
pedal will cause the upshifts to occur at a
lower engine speed.
Automated and Automatic Transmissions
3. Mode
•
Occasionally the road, load, or traffic conditions
make it desirable to restrict the automatic
shifting to a lower range. The lower the gear
range, the greater the engine braking power.
When in Manual mode, push or pull on the
multifunction stalk switch to reach the desired
gear. In the lower gear ranges, the
transmission will not upshift above the highest
gear selected unless the hold override upshift
speed is exceeded.
•
Use neutral and apply the parking brake when
the vehicle is parked with the engine running.
Automatic Mode (A)
In automatic drive mode, upshifts and downshifts are
made by the transmission without driver intervention.
Automatic mode is the default start mode. If in
manual mode, a short push on the shift control mode
switch activates the automatic mode (A). Rotate the
D/N/R switch to Drive (D), and press down on the
throttle pedal. The transmission will shift
automatically.
NOTE: If attempting to select a non-Neutral
mode without applying the service brakes, the
transmission will not shift into gear. To shift into
gear, select Neutral, apply the service brakes,
and select the desired mode again.
In Drive, the start gear is automatically selected. The
transmission automatically performs upshifts and
downshifts.
Manual Mode (M)
In manual mode, the driver selects the maximum
allowed range. This may be helpful when traversing
a work site, railroad tracks, or steep grades, for
example.
When in automatic mode and with the D/N/R switch
set to Drive (D), a long push on the shift control
mode switch activates the manual mode (M). To
increase selected range, pull the lever up (towards
you); to decrease the selected range, push the lever
down (away from you). The transmission will not
upshift above the selected range unless the hold
override upshift speed is exceeded.
See Fig. 14.13 for an example of the driver display
with the transmission in manual mode.
NOTE: The transmission may deny a downshift
if the engine speed would fall outside of the
acceptable range.
14.14