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Electronic Shift Control


Electric Shifter

The budget minded LP7 series is capable of providing the performance characteristics of more expensive electronic shift selectors at a fraction of the cost.


Bennett Electric Shifter S-ES1000-01

For use with the LCT 1000, 2000 / 2400 series

Bolt-on Bennett shift system design, engineered to prevent early transmission failures typically caused by the improper positioning of the transmission�s detent mechanism due to the constant forces applied by stretched or incorrectly adjusted cable shift systems. The Bennett Electric Shifter�s passive, �shift-and-release� operation prevents the inherent backlash problems associated with cables; specifically on rear-engine vehicles where long cable runs must be used.

The precision actuator mechanism of the Bennett Electric Shifter provides incomparable resolution at the transmission selector shaft and allows the detent mechanism of the transmission to determine the selected range. The Bennett shifter families of products are passive devices, meaning; the shifter releases all applied forces from the transmission selector shaft after range selection is made.

The electric shifter is designed to interface with the new LP7 series electronic range selector, as well as other styles of Bennett controllers capable of displaying Park range indication (1000 / 2400 series only). Compatibility with Bennett accessories is ensured as well; utilizing standard harnessing and interfacing with the variety of electronic features offered such as, �Neutral Off�, RPM �Shift Shock�, neutral to range inhibitors, reverse range indication signal, PTO engage and over-speed control.

The primary components of the electric shift system consist of a pushbutton range selector, Electric Shifter Interface (ESI) module, and an integrated Electromechanical Solenoid Firing (ESF) module / solenoid actuated transmission station.

The Electric Shifter Interface (ESI) module mounts in the vehicle cab and is connected to the range selector and the Electromechanical Solenoid Firing (ESF) module at the transmission station via standard Bennett harnessing. The ESI module controls the ESF, which fires the solenoids. Careful consideration was given to protecting the solenoids from being fired simultaneously, as well as preventing the solenoids from being held energized. These issues are easily accommodated by the logic circuitry. The solenoid reaction times are instantaneous due to the 200 millisecond pulse from the ESI. Pulling out of the Park position, accessing each range, and cycling back to Park again can be achieved in a matter of seconds. In fact, the shifter can react as fast as the operator can press the range selector pushbuttons.

The ESI was designed with accessory compatibility in mind. In shift systems where a variety of options are desired, the accessory box or other feature modules can be easily introduced. Accessory box features such as �Neutral Off�, RPM �Shift Shock�, and neutral to range inhibitors, as well as, Seeks Neutral After Shutdown (SNAS) modules (2000 series only) can be connected with little additional harnessing.

Rotation of the transmission selector shaft is provided by two electric solenoids, one each for upshift and downshift. A specially designed solenoid was used that is capable of applying a torque exceeding the minimum 25 lb-ft. required to pull the 1000 / 2400 series out of Park. The second solenoid provides the 3 lb-ft. actuation torque required for all other selector shaft positions. Solenoids were chosen as opposed to a gear motor or linear actuator because of the inability of these devices to be passive. Solenoid actuation provides the �shift-and-release� properties necessary to relieve the applied forces from the selector shaft after the shift is made. Precision positioning with a resolution greater than *Allison�s specification is accomplished via the electric shifter�s internal mechanisms. These are enclosed in a rugged, cast aluminum housing which is o-ring sealed for ingress protection to IP67 classification.

The transmission station is easily installed onto the transmission. It is bolted onto the transmission with an accompanying bracket and linkage and lever to the selector shaft. The mounting envelope of the shifter does not interfere with the NSBU or the PTO mounting pads. Power and interface connections are made with environmentally sealed, over-molded connectors which maintain the IP67 sealing characteristics of the system.

The components of the transmission station were designed for ease of manufacture and maintenance. Solenoid and ESF module replacement, if necessary, are as uncomplicated as unplugging a connector and removing a few bolts. The internal contact arrangement for range indication signaling is also easily accessible from the front cover.

The Bennett Electric Shifter design lends itself to vehicles where pneumatics and hydraulics are not available to power the shifter. Time to production of the electric shifter is scheduled for the end of 2001 following extensive in-house and field testing. However, Stone Bennett Corporation does currently offer a pneumatic shift system for the *Allison LCT 1000 / 2000 / 2400 series transmissions without the Park pawl. The air shifter system paired with the LP7 series electronic range selector provides the same control and precision passive shifting characteristics of the electric device.

All Bennett shift systems are manufactured at Stone Bennett Corporation�s ISO 9001 certified plant in Carrollton, Texas.

*Allison is a registered trademark of General Motors Corporation and is not affiliated with Stone Bennett Corporation.