German transmission manufacturer ZF Friedrichshafen AG introduced the first six speed automatic transmissions in 2001. Since then seven and even eight speed automatics have turned up in various vehicles like Mercedes and Lexus. Now ZF has developed a new torque converter for their six-speed boxes that can lockup sooner, improving mechanical efficiency of the system. They have also revamped the hydraulics and control software to allow it to shift gears twice as fast. All of this apparently results in a three percent improvement in fuel efficiency when mated to gas engines and six percent with diesels. The revamped transmission is already installed in the new BMW 335i and X5 4.8i.

[Source: Automotive News - Subscription required]

Share This Photo X