
Page 88
AT/MT/HT Part Throttle Shift Speed
Description:
The AT/MT/HT Part Throttle Shift Speed parameter
provides the ability to change the shifting
characteristics in vehicles equipped with non-data
link capable Allison transmissions. The Allison AT/
MT/HT (nonelectronic) transmissions require an input
from the engine ECM to regulate transmission shifting.
The ECM monitors accelerator pedal position, engine
speed, load, and cruise control status to determine if the
transmission should use closed throttle or full throttle
shift modulation.
Programming the Transmission Style parameter to
one of the AT/MT/HT options activates ECM Output #7
(J1/P1:20) to control a shift interface relay connected
to the transmission. The ECM can then energize the
output when the transmission should use full throttle
modulation (performance mode) or disable the output
when the transmission should use closed throttle
modulation (economy mode).
Available:
3126E, C7, and C9 medium duty engines. Not available on
2007 and newer engines.
Range:
Alternatives Default
Low (80% Enable/ 65% Disable)
Medium (70% Enable/ 55% Disable)
High (60% Enable/ 45%
Disable)
Advantages:
This parameter provides additional control over shifting
characteristics of the non-data link capable Allison
transmissions. This additional control enables a driver
to optimize the transmission’s behavior depending upon
the specifi c application.
Disadvantages:
None
Engine/Gear Parameters