Allison Transmission Inc. is counting on upgrades to truck and bus fleets in countries like China and India for its future growth, the company revealed in a filing it made Friday to raise up to $750 million through an initial public offering.

The Speedway-based company, which makes automatic transmissions for fire trucks, school buses, garbage trucks and other vehicles, dominates the U.S. market in its category.

Modernization in emerging markets represents a "major growth opportunity," Allison said in its prospectus filed with the Securities and Exchange Commission.

Automatic transmissions, which are beneficial for stop-and-go driving, are typical in North America, with nearly 79 percent of medium- and heavy-duty trucks sold last year equipped with them. By contrast, fewer than 5 percent of commercial trucks sold overseas were equipped with automatics, according to Allison's research.

Allison noted that more Chinese cities are using garbage trucks to collect household waste, and Indian truck makers are utilizing more modern equipment.

Allison has a foothold in China, where its product is in 30,000 vehicles, and in India, where it established manufacturing in 2010. Later this year, it expects to open a smaller manufacturing facility in Hungary in a partnership with its former parent company, General Motors.

At this point, however, Allison's major presence is in the United States, where it derived 73 percent of its 2010 sales of $1.9 billion.

After two years of losses exceeding $300 million, Allison turned a $29.6 million profit in 2010. Over the past three years, the company also boosted its  investment in research and engineering so it has "more new products under development today than at any time in our history," it said.

Aided by a Department of Energy grant, Allison is working on a hybrid-propulsion system for commercial trucks. The company is also developing a transmission for tractor trucks that spend the majority of their time in cities. Allison has little presence in the heaviest truck class, so the new transmission could add a brand-new revenue segment.

Among the risks Allison noted for would-be investors is its $3.7 billion in debt.

Another is a heavily unionized workforce. About 60 percent of its 2,750 employees worldwide are represented by the United Auto Workers, whose contract expires in 2012. Allison considers its relations with UAW Local 933 to be good. The company noted that 60 percent of its total workforce, both salaried and hourly, is retirement eligible, which could mean cost savings in the future.

GM spun off Allison in 2007 to private-equity owners Carlyle Group and Onex. Allison expects that its two "sponsors" will continue to control a majority of voting rights after the IPO.

CEO Lawrence Dewey owns 1.1 percent of current stock. Dewey, 54, has been with the company since 1989 and earned a base salary of $437,500 last year.