PREVOST H 2018 Series, Operator'S Manual

Page: 105 / 258

CONTROLS AND INSTRUMENTS 4-63
PA1628 H3-41, H3-45 Operator’s Manual
ALLISON TRANSMISSION
The transmission is fully automatic: Proper
ranges should be automatically selected
according to driving speeds to improve vehicle
performance and control. The speed ratio of the
power converter changes automatically as
vehicle speed increases and direct-drive goes in
and out as necessary. The speed ratio is
modulated by vehicle speed and accelerator
pedal position. You will find the complete
transmission operation instructions and driving
tips in the
Allison 5
th
Generation Bus Series
Operator’s Manual
included in your vehicle’s
publication box.
OPERATION
When a button is depressed on the transmission
control pad, the corresponding letter or number
is displayed indicating the transmission is ready
to operate in the selected range. If the
transmission control module (TCM) detects a
serious problem in the transmission, the CHECK
telltale lights on the dashboard.
ALLISON PUSHBUTTON SHIFT SELECTOR
07142
PUSHBUTTON SHIFT SELECTOR
The pushbutton shift selector has the following
elements:
R
: Press to select Reverse gear.
N
: Press to select Neutral.
D
: Press to select Drive. The highest forward
range available will appear in the digital display
window under SELECT. The transmission will
start out in the lowest available forward range,
displayed under MONITOR, and advance
automatically to the highest range.
: Press respectively the (Upshift) or
(Downshift) arrow button when in DRIVE to
request the next higher or lower range. One press
changes gears by one range. If the button is
held down, the selection will scroll up or down
until the button is released or until the highest
or lowest possible range is selected. Protection
mechanisms inhibit selecting ranges that are not
appropriate for the current speed or which may
damage driveline components.
MODE
: Pressing the MODE button allows the
driver to activate the secondary shift schedule
that has been programmed into the TCM unit.
PRIMARY AND SECONDARY SHIFT SCHEDULES
The
primary shift schedule
is the default mode
at starting of the engine and is typically
specified to accommodate normal vehicle
operation. The
transmission controller
automatically selects between ECONOMY and
PERFORMANCE shift strategy, based on the
vehicle actual load and the grade on which the
vehicle is operating. This is called Load Based
Shift Scheduling (LBSS). This can produce
improved overall vehicle fuel economy while still
enabling high productivity when the vehicle is
loaded.
In the
secondary shift schedule
, only the
ECONOMY shift strategy is available. No
switching is done between shift strategies. The
secondary shift mode is available only if selected
by the driver, using the MODE button. When the
secondary mode is activated, “MODE”
illuminates on the display.
NOTE
When the diagnostic display mode has been
entered, the MODE button is used to view and
toggle through diagnostic code information.
Refer to appendix C for more details about
diagnostic code display procedure
and
fluid
level check using the pushbutton shift
selector.