海角大神

Like it or not: Nearly every new vehicle鈥攚e're talking around 95 percent鈥攈as an聽automatic transmission聽of some sort. And manual transmissions are rare today, except among a few performance-oriented models.

That's the obvious. What might not be so apparent to new-car shoppers is that the portion of聽vehicles聽with automatic transmissions鈥攐r at least automatics as we know them鈥攊s 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鈥攖he CVT鈥攊s 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鈥檙e often the single most expensive component in a聽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 affective 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.

Both of these transmissions are quite simple in theory and elegant in layout, but there are some hurdles in the execution; and getting them right鈥攁nd getting them to effectively be what we expect an聽automatic transmission聽to be鈥攄epends tremendously on calibration, software, and tuning.

And their flaws are completely different, which makes them each well-suited for some kinds of cars and ill-suited to others:

Dual-clutch automatics tend to offer snappy, coordinated shifts when you're driving quickly鈥攁nd a little more driving enjoyment than a typical automatic鈥攂ut at low speeds they're often not very well coordinated.

Continuously variable automatic transmissions (CVTs)鈥攐ften considered the uninspiring alternatives鈥攌eep the engine in its sweet spot for acceleration (or fuel-efficiency) but often to the detriment of noise and vibration, leading to complaints of a disconnected, 'motorboating' feeling when accelerating鈥攊n which the note of the engine isn't connected to a sensation of speed. At their worst, CVT transmissions can feel sluggish, or as if something is uncertain or slipping.

CVTs at 10 percent and growing

Among new vehicles with automatic transmissions, more than ten percent now have CVTs, and that percentage is growing each model year. That's because it's not just niche models; top-selling models like the Toyota Corolla,聽Honda Accord聽and Honda Civic now have CVTs on their most popular models, as do family mainstays like the Subaru Outback and Forester.

鈥淐VTs have proven that they work much better on mainstream vehicles,鈥� said Jake Fisher, director of聽auto聽testing for Consumer Reports.

CVTs typically offer fuel-efficiency gains that are as big as those brought by eight- and nine-speed automatics, yet they cost less. That's part of the reason why Nissan鈥攁nd CEO Carlos Ghosn鈥攑ursued them as a long-term commitment back when they were an unpopular option that few other automakers embraced in a big way.

It hasn鈥檛 exactly been a smooth road, either. Chrysler and Ford both tried CVTs in many of their vehicles, then backed away, with consumer acceptance part of it.

That commitment has proven a mixed bag over time for Nissan. The automaker has had some quality concerns and issues with perception for its CVTs, and most recently, Consumer Reports has seen some issues with the JATCO transmission in the Altima. 鈥淲e currently don't recommend the Altima,鈥� said Fisher, 鈥淎nd reliability鈥攁nd the CVT鈥攊s part of it.鈥�

Fisher thinks that CVTs are at a natural disadvantage against the latest and best automatic transmissions, and that it's mostly a perception issue, not an issue of performance.

CVTs rationally better, but lacking the driver connection

鈥淲ith anything that follows fixed ratios, you have the direct connection,鈥� he explained, and that makes the driver feel more satisfied and in control. 鈥淎cross the board we鈥檝e seen this鈥攖hat the CVT improves fuel-efficiency, decreases satisfaction,鈥� said Fisher.

And a number of automakers are finding ways to calibrate their CVTs in ways that restore that feeling of connectedness for the driver. For instance, recent CVTs in Honda, Subaru, and Toyota models will all 'catch' particular ratios during acceleration and follow them up the rev range鈥攑robably paying a very slightly penalty in efficiency or performance鈥攊n order to maintain more of a 'natural,' seat-of-the-pants feeling of acceleration.

Dissatisfaction with CVTs has, now and in the past, been less related to performance as it is to noise, Fisher says, and that's why some of the latest CVTs make slight sacrifices in performance in order to provide a more satisfying sound. The transmission in the Honda聽Accord聽is especially fairly impressive for that, he notes. 鈥淎nd really it鈥檚 a small price to pay for better noise characteristics.鈥�

But there's no substitute for a set, predictable ratio that you can lock in, when you're on a mountain road, a steady downhill grade, or even a racetrack situation. 鈥淐learly the manufacturers hear this, and that鈥檚 why they鈥檙e putting in fake ratios which, ironically, hurt performance,鈥� said Fisher.

In the 2015 Subaru WRX, for instance you can tap into eight simulated ratios in a dedicated mode, while the Nissan Juke has a similar feature; and even the聽2014 Toyota Corolla聽S offers seven 'speeds.'

There are plenty of indications that all the effort is working with consumers鈥攖o the extent that some owners might not even know they have one.

鈥淚n our latest聽Vehicle聽APEAL Study (2013 MY), owners with CVTs reported virtually the same satisfaction levels as owners with manuals or traditional automatics,鈥� commented David Sargent, J.D. Power's vice president, global automotive. The APEAL study examines what consumers like about their new vehicle after 90 days of ownership.

Maintenance: where traditional automatics still have the advantage

Although CVTs might offer a cost advantage to the automaker, and help keep sticker prices down, they're not necessarily lower in upkeep to the owner. At a time when many conventional automatic transmissions are sealed and essentially maintenance-free for 100,000, or more in some cases, many CVTs might require rather costly fluid changes鈥攚hich can also quickly erase any money saved on a slightly fuel-economy advantage.

But much of the data shows that CVTs are leaving owners satisfied. In J.D. Power鈥檚 latest Vehicle Dependability Study (VDS), which goes back three model years (2011, in this case), CVT聽vehicles聽had the lowest rate of engine/transmission problems.

As for dual-clutch gearboxes, they're hardly maintenance-free either. For instance, VW's DSG still surprises owners with its requirement for fluid and filter changes at 30,000-mile intervals鈥攆or several hundred dollars a pop.

The one-track mind of dual-clutch gearboxes

鈥淭here are clearly a lot of issues with dual-clutch gearboxes,鈥� said Fisher. 鈥淲e don鈥檛 see a lot of them in high-volume models, and there's a reason for that.鈥�

鈥淲e see a lot of vehicles with jerkiness,鈥� especially at low speed, explained FIsher. 鈥淎nd as the clutch wears, you end up with these situations where there鈥檚 a non-linear power delivery.鈥�

Fisher pointed out that you need only take a cursory look at federal (NHTSA) complaint data for certain models to get an idea of how commonly dual-clutch gearboxes are malfunctioning, or at the very least misunderstood.

Like CVTs, dual-clutch transmissions offer the potential for greater performance (by the stopwatch) and better fuel economy, compared to regular automatic transmissions, yet they sacrifice some drivability and general smoothness to get that.

Many of the dual-clutch gearboxes seem to be tuned for top performance, Fisher observes. 鈥淲ith all these, zero to 60, or quarter-mile, they鈥檙e flawless. It鈥檚 in the mall parking lot where they can be a disaster...in those extended drives, in transitions, where they鈥檙e on and off the gas.鈥�

Ford has gradually improved the software controlling its PowerShift dual-clutch gearbox that's used in the Focus and Fiesta鈥攖o the extent that it's expected to renew its vows with them in next-generation versions. Chrysler, meanwhile, has been withdrawing from plans to put its DDCT dual-clutch gearbox in more U.S.聽vehicles; after a lukewarm reception, it's only now offered in one trim level of the 2014 Dodge Dart (the Aero), and in the Fiat 500L.

鈥淭hey鈥檙e having a hard time getting these smooth鈥� for U.S. driving conditions, said Fisher. 鈥淚t鈥檚 very confused in the 500L.鈥�

CR recommends staying away from it, as well as from the Ford unit. 鈥淎lthough Ford has really worked hard to get it better,鈥� Fisher said.

Myths versus reality

There鈥檚 no reason to believe that a CVT will be any less reliable than a conventional automatic, or have fewer trouble-free miles overall. That's confirmed through Consumer Reports reliability data, which is based on on detailed responses from subscriber experiences with 1.1 million vehicles.

Longevity is another myth; with the exception of some early V-6/CVT combinations, which we shall refrain from mentioning here, there are no indications that CVTs have a shorter life cycle.

Of course, there are some indications that say otherwise. In J.D. Power's VDS鈥攁gain going back three model years鈥攖hose owning vehicles with dual-clutch gearboxes report the highest satisfaction.

But it's also hard to say that either CVTs or dual-clutch gearboxes are pushing the versatile, refined traditional automatic transmissions out of the market鈥攅specially at the premium end of the market. Fisher points to the ZF eight-speed automatic transmission that's used in a number of luxury and performance-oriented聽cars聽as an example of just how good conventional automatics can get. Versus that, and some other newer multi-speed automatics, Fisher, argues, 鈥淚 don鈥檛 think you鈥檇 point to the CVT and say that it鈥檚 superior, in terms of how it drives.鈥�

Are you sure you won't go manual?

The percentage of聽new vehicles聽sold with a manual transmission has fallen to around five percent鈥攍ower by some calculations. That change is easy to see, for anyone who remembers the greater number of manuals on lots just, say, 10 or 15 years ago.

Although CVTs, and even some dual-clutch gearboxes, get better EPA mileage ratings than manuals, a manual gearbox, driven properly, is still the transmission choice with the lowest cost over the long run, Fisher says.

And while shifting it yourself is still in vogue for a certain kind of performance聽car, manual-shift versions of mainstream models鈥攆rom cost-conscious sedans to rugged crossovers鈥攃ontinue to disappear from the market at what is (to us) an alarming rate. Meanwhile, there鈥檚 no doubt that smartly tuned CVTs will be appearing in more new models.

So do you want a car with gears? Do you want to shift? Or would you rather not even care to notice most of the time? Just be aware that you have plenty of choice in that.