2014 Honda Civic EX CVT - DrivenEnlarge Photo
That's the obvious. What might not be so apparent to new-car shoppers is that the portion of vehicles with automatic transmissions—or at least automatics as we know them—is falling, too. And because of what's replacing them, you, as a smart shopper, should understand the differences so that you get the right kind of running gear to meet your expectations.
So-called conventional hydraulic automatic transmissions, typically today with five to nine dedicated speeds (gears), aren't going away anytime soon; but two other alternate designs, dual-clutch gearboxes and continuously variable automatic transmissions (CVTs), both claim improvements in both performance and fuel efficiency. And one of them—the CVT—is gaining traction in the market at a far faster rate.
Both of these newer types boast some pretty pronounced advantages in mechanical simplicity over those conventional automatics, with their multitude of gears, solenoids, and hydraulic valving (they’re often the single most expensive component in a vehicle, before the engine in many instances).
Both simple in design, but potentially flawed in delivery
The idea behind CVTs is easy to understand: a heavy-duty drive belt (or chain) runs within a grooved pulley system with hydraulic actuators allowing the effective ratio to be infinitely varied within a range of ratios, seamlessly.
As for dual-clutch gearboxes, there are two separate automated manual gearboxes, each with its own clutch, but one containing the odd gears and the other the even ones. So, for instance, as you're accelerating, each respective gearbox readies the next gear up.