Allison Transmission announced its first nine speed model at the North American Commercial Vehicle Show in Atlanta.

The fully automatic transmission, for medium and heavy duty vehicles, will be available worldwide after release in 2020.

"With this new transmission, Allison continues to demonstrate its commitment to help achieve standards regarding fuel efficiency and greenhouse gas (GHG) emissions," said Randy Kirk, the supplier's head of product engineering and product teams.

"This release coincides with the timing of the Environmental Protection Agency (EPA) Phase 2 GHG and Fuel Efficiency Standards."

With its deep first gear ratio and claimed industry leading ratio coverage, the new transmission is said to provide "significant fuel savings as the highly-efficient gear train allows the torque converter to lock up early in first gear". It also includes an integral engine stop start system which provides immediate transmission engagement and vehicle hold while the engine is restarted.

Allison sees it as "ideal for distribution trucks, rental and lease trucks, and school buses".

"When combined with FuelSense, our software and electronic controls packages, and our other fuel saving technologies, the nine speed will set a new benchmark in fuel efficiency and reduced emissions, achieving Greenhouse Gas Emissions Model (GEM) benefits," claimed Kirk.

"Many OEMs in North America, Europe and Asia have expressed interest with prototype evaluations beginning for them this year."

The nine speed 'box will replace its "proven durability" 2000 Series six speed predecessor transmissions which collectively have accumulated more than 100bn miles globally. It's been designed to use the same OEM interfaces as the six speed, providing ease of integration into vehicles currently using that transmission.