Transmissions didn’t make great talking points 12 years ago. Most cars either came with 4-speed automatics or 5-speed manuals. Expensive sports cars used 6-speed manuals, and a few luxury cars came with 5-speed automatics. Two decades before that, it was mostly 3-speed automatics and 4-speed manuals. There was nothing more to say.

But when ZF introduced a conventional 6-speed automatic in 2000, transmissions became a steeplechase. Three years later, Mercedes followed suit with the 7-speed automatic. In 2008, Lexus did an 8-speed. Dual-clutch 7-speed gearboxes, an evolution of Ferrari’s herky-jerky F1 transmission from 1997, rolled out on the 2009 Porsche 911 and European Volkswagen models (four years after debuting on the Bugatti Veyron).

And now? Porsche has a 7-speed manual – with an entirely new shift pattern – and ZF is introducing what will likely be the world’s first 9-speed automatic (pictured above) for 2013 Dodge and Chrysler products.

We have reached fully barstool-worthy conversation.

The gear race

The demand for ever-lower fuel consumption – plus the industry's desire for constant one-upmanship – is making this leap in gears possible. It’s leading ZF, one of the world’s leading transmission manufacturers, to open a million-square-foot plant in Greenville, S.C., that will churn out 800,000 8- and 9-speed automatic gearboxes by next year.

But have we reached a plateau, now that we’ve nearly matched the number of gears found on bicycles and 18-wheelers?

“We do not design according to the number of gears. We design according to the best fuel economy and customer value,” said Dr. Ludger Reckmann, president of ZF Greenville. “For rear-wheel-drive, it was eight speeds. And for the consideration for a transverse transmission, the outcome was a 9-speed.”

Having driven a few new cars with ZF’s 8-speed automatic – the BMW 6-Series, Audi A8, Porsche Cayenne, and Dodge Charger – the obvious benefit is a low-revving engine at highway speeds. At 70 mph, these engines are practically walking at about 1,500 rpm, or nearly a thousand short of other engines in most cars. It’s almost diesel-like. Slam the gas, and in sporty cars like the BMW the transmission will bang out an ultra-quick 8-2 shift and then ease right back up the ladder when you’re done passing. No manual can match that kind of speed, smoothness and peaceful engine revs.

Will we see 10- or 11-speed gearboxes after this? Reckmann won't rule it out.

What about CVTs?

Continuously variable transmissions, which are used heavily by Nissan and hybrid manufacturers like Toyota and Ford, are also adept at keeping the engine at maximum torque and low revs. In performance driving, however, it can feel like a clutch is slipping as the engine whines at a fixed RPM. While Nissan fully defends the CVT, ZF, which used to make CVTs for Ford, isn't convinced it's worthwhile anymore.

“The disadvantage of a CVT is that those [pulleys] always have to be under pressure from an oil pump, and this oil pump creates lots of efficiency losses,” Reckmann said. “And you have certain limitations with the final gear ratio. We ended up with a gear ratio of six or so.”

What about dual-clutch automatics?

Dual-clutch automatics, like those on the new Ford Fiesta and diesel Volkswagens, aren’t saturating the global market beyond super-sporty Ferraris and Porsches. Right now, ZF builds more than 1 million 8-speed automatics per year, or about 10 times its number of dual-clutch automatics. While more efficient and faster-shifting than most conventional automatics (there is no torque converter, just two automated clutches), DCTs are about 10 to 15 percent pricier, Reckmann said. They also behave more like manuals than true automatics, with rougher shifts and the tendency to roll back and slip the clutch on hills. And Americans, as Car and Driver has pointed out, hardly line up to buy manuals. 

Bogging engines

When asked about software programming, Reckmann said that ZF works closely with each automaker to develop specific shift points. This is where it gets annoying. On the 2012 Volkswagen Tiguan, for example, the 6-speed Aisin automatic is now in the wrong gear at all the wrong times. Want to speed up slightly from 30 mph? Instead of speeding up, you have to press further than normal while the transmission hunts down a gear or two, resulting in unpredictable acceleration.

In the Range Rover Evoque, engine clatter vibrates through the steering column because the transmission (a ZF 6-speed) is in top gear when it should really be in fourth. The new Mazda 3 with its Skyactiv 6-speed automatic behaves in exactly the same way. It’s an attempt to gain higher EPA ratings at the very big expense of driver comfort.

“The software is a very customer-oriented product,” Reckmann said. “Sometimes my impression is that the car manufacturers tweak the software toward best fuel economy, and that sometimes jeopardizes performance and quality.”

I could go on and on about transmissions. Meet me for a drink in Boston and we’ll talk.