Aisin AW Company, a Toyota affiliate that makes automatic transmissions and car navigation equipment, says it is developing a gas-electric hybrid power train system for the Ford Escape sport-utility vehicle. The hybrid is expected on the market by 2003. Hybrids combine an electric motor with the regular internal-combustion engine to deliver more mileage and less pollution. Toyota has taken a lead in hybrid technology with its Prius compact car, which went on sale in Japan in 1997. No one is predicting that Toyota will end its marriage with General Motors, its longtime U.S. ally. Japan's leading automaker has an agreement with the Detroit automaker to work together on hybrids and other ecological technology. But Toyota's alliance with Ford underlines the rise of critical partnerships among the world's top automakers to keep up with cost-cutting pressures and technological advances, according to industry analysts. Toyota declined comment on the Aisin-Ford news, saying it was a matter for Aisin AW. But Toyota officials have repeatedly acknowledged it is in talks with Ford looking for possible deals. Ikuno Fujii, Ford spokeswoman in Tokyo, said Ford has been in talks with various companies but was not prepared to make any announcements. Aisin AW spokesman Hirotake Kondo said that his company will receive funding from Ford to develop a hybrid similar to the Prius, although details have yet to be worked out. Kondo stressed that the deal would not be happening without Toyota's blessing. Toyota owns about 40 percent of Aisin AW, based in central Japan. Hybrids are expensive and analysts say it makes sense for Ford to buy the technology from a company that already sank the money into research and development. It also makes sense for Toyota to sell Ford a hybrid technology from its affiliate because that would help spread the technology outside Japan, they say.