Mack M359, Руководство пользователя

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STARTING AND DRIVING
ALLISON TRANSMISSION
the transmission automatically upshifts
through each range. As the vehicle or
equipment slows down, the
transmission automatically downshifts to
the correct range. The SELECT display
shows the highest range available in D
(Drive).
NOTE
The vehicle OEM or bodybuilder is
responsible for evaluating the driveability
of shift schedules in the intended vehicle
and duty cycle. For additional details
regarding these shift schedules and/or
other options for primary and secondary
shift schedules, contact a qualified Allison
Transmission service outlet for further
information.
Upshifting
As long as the Transmission Control
Module (TCM) calculates that there is
enough vehicle power and vehicle
acceleration available to grant and keep
the next upshift, then there are no other
limitations imposed on upshifting until
the vehicle attains its top range
displayed in the SELECT display on the
selector. Vehicle power and acceleration
characteristics are monitored by the
transmission controls to attempt to
eliminate shift cycling. Shift cycling is an
upshift followed closely by a downshift,
which is then followed by another
upshift, and so on.
NOTE
If shift cycling is noted, use the alternate
shift schedule by pressing the MODE
button. The operator can also manually
select the next lower range (using the shift
selector) to hold that lower range until
conditions are met to grant the upshift
point again without shift cycling.
Hold Schedule for Upshifts
As a standard feature of each shift
calibration, the transmission controls
incorporate a "hold upshift" shift
schedule, which the operator may select
if the transmission is not operating in its
highest range. When this schedule is
active, the shift points for upshifts are
raised in order to hold the transmission
in its current gear and inhibit upshifting
beyond the current range. Holds are
activated by selecting the current range
or a lower range on the shift selector.
CAUTION
A typical use of the "hold" feature is to
maximize engine braking when operating
downhill. However, in order to prevent
overspeeding the engine, the hold
function is not infinite. It will permit shifts
from the hold range to the next higher
range at some speed above the shift
calibration speed.
Downshifting
Downshifts are allowed to occur as long
as transmission output speed is low
enough to keep from overspeeding the
engine after completing the downshift.
When a range downshift is manually
selected by the operator, but the
transmission output speed is
determined to be above the limits, the
transmission remains in the range even
though a lower range was requested by
the operator. A shift to a lower range can
occur when the operator applies the
vehicle service brakes or a retarding
device, such as an exhaust brake,
engine brake, or retarder. This action
reduces the transmission output speed
which in turn lowers the vehicle speed,
allowing the transmission to shift to the
lower range.
Preselect Schedule for
Downshifts
The preselect downshift schedule is
similar to the hold feature. The operator
may initiate the preselect downshift shift
schedule by selecting any forward gear
on the shift selector that is lower than
the gear currently in use. When a range
has been "preselected" in this manner,
shifts to and from gears above the
preselected gear range occur at higher
than normal engine speeds. Shifts below
the preselected range are not affected.
Preselect downshifting is beneficial in
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