INDIANAPOLIS With revamped diesel engines just a couple of months away from widespread introduction by truckers and somewhat later by motorcoach operators, Allison Transmission has announced a series of product improvements for the new model year.

Allison, the world leader in medium- and heavy-duty commercial transmissions and the No. 1 transmission supplier to the motorcoach industry for decades, says its transmissions have been "optimized" for 2010, meaning efficiency and fuel economy features have been enhanced.

"Weve always been committed to understanding and satisfying the needs of our customers. Thats why we constantly analyze, refine and improve our products and features," said Jim Wanaselja, vice president, Allison Transmission North America marketing, sales and service.

For 2010, Allisons "load-based shift scheduling" feature includes a "super economy shift schedule." The upgrade allows Allison transmissions to up-shift under cruising conditions to improve fuel economy.

The load-based shift scheduling feature automatically selects between economy and performance shift schedules based on the vehicles payload and the grade on which it is operating.

The shift feature is available on all bus, highway and pupil transport/shuttle series transmissions.

The super economy feature also is available with "shift energy management/low-range torque protection" (SEM/LRTP) capable engines.

The 2010 Allison 1000/2000 series transmissions feature increased horsepower and torque ratings, allowing a broader range of applications at a lower initial cost.

The 1000/2000 trannies, with shift energy management, are now rated up to 340 horsepower and 660 pound-feet of torque. Without shift energy management they are rated up to 300 horsepower and 575 pound-feet of torque. Ratings may vary by model and application.

Hardware enhancements to all 2010 1000/2000 Series models have reduced the power required to charge the oil lube-distribution and main-pressure system. The introduction of this "variable modulated main" feature reduces main pressure when the clutch apply system does not require full main pressure. New wave friction plates reduce internal drag, resulting in more efficient operation that helps improve fuel economy, says Allison.

A new "vehicle acceleration control" feature helps control aggressive driving practices and improve overall fuel economy. The VAC feature limits acceleration by controlling the amount of engine torque based on vehicle load.

Allison says that tests using a simulated bus duty cycle show VAC helps improve fuel economy by as much as 3 percent. VAC is available on bus and pupil transport/shuttle series models.

Also new for 2010, Allison B 300 and B 400 models are available with "increased lockup availability." This feature enables the transmission to shift into lockup in first range, and lockup stays on through first to second shift. The transmissions electronic controls monitor acceleration to determine when to activate lockup. Application engineering review is required for this feature.