Editorial: Sticking a nose into the great transmission debate

Never ones to shy away from a good argument - even if it is someone else's - we just have to poke our noses into the debate that's occurring over at The Truth About Cars concerning VW's dual-clutch transmission (DCT).

To start things off, Mr. Farago argues that the DCT (he uses the VW trademark "DSG", or Direct Shift Gearbox) should signal the end for manual transmissions. His colleague Bob Eaton responds by claiming that the DCT is just another variation on the automatic, and makes it clear that his favorite horse in this race is the familiar planetary slushbox.

We, of course, have our own opinion, so keep reading if you're curious.



To begin, I'd like to point out that the DCT doesn't employ any overrunning clutches (also known as "sprags" or "mechanical diodes"), at least not in the strictest definition of the term, and this pokes a fairly sizeable hole in Elton's third-to-last paragraph. Traditional automatics use such devices to allow the engagement of two or more gears at the same time; the one that attempts to spin the output shaft the fastest is the one that transmits the power to the road. This is why automatics provide no transmission braking when Drive is selected. DCTs, on the other hand, depend on the smooth handover of power through two coaxially-mounted clutches, with elaborate mechatronic controls being the only thing preventing a gear-shredding catastrophe (it's for this reason that DCTs employ normally-open clutches, so that a power failure results in a free-spinning drivetrain). Therefore, there's really no reason to claim that a DCT is just another variation on the automatic architecture; in fact, the overrunning clutches in many modern automatics have been replaced by clutch-to-clutch shifts, just like a DCT.

The other important point to make about DCTs is that they're built using production processes much like a traditional manual transmission. Many of the internal components of a DCT resemble those of a manual - much more so than an automatic, in fact. As such, it's significantly easier to take capital equipment that's currently manufacturing manuals and use it for DCT production rather rework the same equipment to build planetary automatics. Considering the huge amount of production capacity currently available for manuals, especially in regions like Europe, this could have enormous impact on the direction of future transmission trends. We'll soon see DCTs from manufacturers other than Borg-Warner and yes... some will even make their way into U.S.-badged vehicles.

I think where Eaton, Farago, and myself lie in agreement, though, is that manuals are dead. The lines between an "automatic" and a "manual" will be erased over the next decade or so (maybe less), with mechatronic systems doing the dirty work through a combination of electric and hydraulic actuators. The time is right, and many would argue that it's been right now for at least of couple of decades. In many cases, wider gear ranges and wet-clutch launch systems will replace the torque converter; frankly, this has already happened to some extent with progressively-locking multiplate locking converters. At this point, everything's "automatic," and that term ceases to hold any specific meaning.

A huge factor in this, of course, is that the future growth potential in the car industry lies almost entirely in developing nations. If someone has never driven a car before, does it make sense to complicate the task with two additional driver control devices and a difficult-to-master technique involved three of the user's limbs? This hardly sounds like a recipe for success.

Drivers may still have some means of "manual" input, but these will be treated as suggestions, just as is the case with modern electronic throttle control (ETC) systems. The difference between a vehicle that is responsive to driver inputs and one that is not will largely be a function of software, and that should be very exciting to technologically-savvy consumers, as it's much easier to change a few lines of code than it is to fit a short-throw shifter to a manual transmission, or go digging through the valve body of an automatic. Sure, some will complain, but we'll simply file away those folks in the same category as those who that haven't yet managed to wrap their heads around making the transition from carburetors to EFI. I might even suffer a pang of nostalgia as I think about the joy of digging through a pan of ATF while looking for a check ball, but I assure you it won't last for long.


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