Allison Transmission has begun offering its xFE fuel-saving technology on two more of its medium-duty transmissions, including the 1000 Series and 2000 Series, the company has announced.

The xFE technology, which stands for extra fuel economy, can improve fuel efficiency by 7% when compared to baseline models. The technology was previously available on select 3000 Series models.

The 1000 Series and 2000 Series transmissions are usually paired with smaller medium-duty trucks and buses. They offer the same ratings as current models and incorporate a redesigned torque converter damper coupled with the FuelSense 2.0 Max package. The damper enables first range lock up and delivers significantly more lock up operation, according to the company. They operate at lower engine speeds in higher ranges to further improve fuel economy. The xFE transmissions are compatible with alternative fuel engines.

Allison debuted its xFE transmissions in 2015 for 3000 Series buses. FuelSense 2.0 with DynActive shifting debuted in March. Allison employs a series of software enhancements to provide a variable combination of shift points and learning algorithm that searches for the ideal balance of fuel economy and performance.

Allison transmissions also use Continuous Power Technology to smoothly multiple engine torque and deliver more power to the wheels.