A leading executive from German transmission manufacturer ZF says the group’s nine-speed automatic transmission that is about to be launched in several Chrysler models in the US is the limit of efficiency.
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In an interview with CarAdvice, ZF Asia Pacific managing director Joseph McCorry said transmission technology had reached a ceiling in terms of efficiency gains from adding extra ratios.

“From an engineering point of view, if we’re looking at speeds, going from a four-speed and then a six-speed is the ultimate and then an eight-speed and now a nine-speed, what we start to get to is efficiency maximum,” McCorry said.

Nine-speed transmission - ZF

He believes enhancing efficiency beyond a nine-speed transmission will prove difficult.

“We’re very close to the edge of optimising efficiency at nine.”

ZF products, from transmissions to steering components, feature in many different brands including BMW, Mercedes-Benz, Jaguar, Porsche and Volkswagen, as well as Holden and Ford.

Joseph McCorry - ZF

In response to suggestions of future 10-speed transmissions, McCorry said the continued development and advances in technology make him hesistant to say there won’t ever be a 10-speed, but insisted ZF would not come out with one next year.

“Could you go to a 10-speed? Maybe. But then it’s [a question of] what is the cost benefit? And I hate to say there’ll never be a 10-speed because people when there was a six-speed said well, will there ever really be an eight- or a nine-speed?”

This efficiency limit could mean an end to the gear ratio war that has seen more and more gears added to gearboxes over the past few years.

Ford Territory

“We didn’t make the nine-speed so that we could say we put a nine-speed into it, we did it to be efficient. If someone comes out with a 14-speed and it’s one millionth of a per cent better, we’re going to say, ‘good for you’.”

McCorry says the future for gearbox technology will be focused on the materials individual parts are constructed from.

“The challenge we have right now is the cost benefit ratio. It has to do with efficiencies in terms of friction, so we are looking at new materials, new alloys, and ceramics.”

Holden Commodore VE Series II SV6

As far as ZF’s ties with local manufacturers Ford and Holden, McCorry said, provided those brands were manufacturing in Australia, ZF would be in Australia.

“As long as they’re here, we’ll be here.”

The six-speed automatic transmission found in the Ford Falcon and Territory and steering modules in the Holden Commodore are both ZF items.