Buhler 435 Lawn Mower User Manual


 
3-64
435/485/535
Section 3 - Operation
Transmission Operation
Rules of Operation
During autoshift, all manual upshifts and downshift
requests using the bumpshift lever to upshift /
downshift will be utilized to change the max gear
limit. All shifts will be performed automatically based
to autoshift shift points.
During autoshift, if the inching pedal is pressed or if
the shifter is placed into Neutral, the function will be
terminated immediately.
Upon inching pedal release or placing the shifter
back into gear, gear selection will be based upon
the selection made by the Speed Matching
function.
If the inching pedal was pressed down or the
shifter placed into Neutral while operating in a gear
that is at or above the max allowed launch gear, and
if the tractor coasted to slow speeds or stop, unless
changed by the operator while the inching pedal is
down or in Neutral, the max allowed start gear will
be used to launch the machine.
Otherwise, the gear previously operated in that is
below the max allowed launch gear will be used.
The transmission will not resume autoshift mode
until the operator request the activation autoshift
through the auto function switch.
If a shuttle shift is attempted while in autoshift,
the shuttle shift will be initiated through the normal
shuttle shift routine and autoshift will be
disabled.
Autoshift
This auto shift mode can be used to simulate the
functionality of a typical automatic transmission on an
automobile. Machine speed is controlled by throttle
position and load. The transmission will upshift to the
maximum sustainable gear and downshift when load
increases or speed reduction is requested.
Autoshift mode can be used to achieve the maximum
performance of the machine. If the load to the
machine increases and the engine is lugged down
below the optimum operating point in any gear, the
transmission will automatically downshift to provide
optimum performance. When the load condition has
passed, the transmission will automatically upshift to
maximize speed and output of the machine.
Transmission shift points are determined by
transmission output speed (engine speed).
Once in autoshift mode, selecting a certain gear
using the shifter will set the maximum gear that the
transmission can operate up to. For instance, if the
operator upshifts to F12, then the machine will only
shift up to F12, even if it is capable of operating in
gears above F12. Similarly, if the max gear is set at
F12 and the machine is loaded and only capable of
operating in F9, then it will stay in F9 until the load
condition has subsided.
NOTE: The autoshift mode is meant to operate with
the throttle set to full. If operating at part throttle,
the machine may not upshift because the upshift
point might not be reached at part throttle conditions.
Similarly, if the throttle is lowered to the point where
the downshift point is reached, it will downshift even
if the machine is not loaded.
Autoshift Enable and Termination
The autoshift mode will be engaged through the use
of the momentary SPDT auto function switch (1).
Press and release the front/symbol of the switch to
engage autoshift. Press and release the switch again
to disengage the autoshift function. The letter “A”
will be displayed in the powershift display (2) when
autoshift is engaged.
Once engaged, the transmission enters autoshift mode
between F1 and the max gear limit set to the current
desired gear. The operator is then allowed to upshift or
downshift to change the max gear limit.
When autoshift mode is disengaged through the use of
the auto function switch, the transmission will remain
in the current gear and enter manual shift mode.
F3-138
GEAR
F3-139
AUTO
1
2