Volkswagen Group's DSG Gearbox Explained

Adolphe Kegresse is the French pioneer in question, but due to unfortunate developments, he never got to finish a working model of said box. It was intended for the front-drive Citroen Traction Avant, namely the world's first mass-produced FWD automobile. It was also featured the world's first mass-produced monocoque.

The double-clutch setup would have to wait another two-something decades before a model dubbed Hillman Minx Series III would be offered with the Smiths-developed Easidrive. Among many other things, Easidrive features two electro-magnetic clutches. Rather archaic electronics together with solenoids were used to enable gear shifts, but alas, said tranny proved unreliable.

Many owners preferred to replace them with a synchromesh manual. Given the aforementioned, the dual-clutch transmission would have to wait another two-something decades before a PDK-equipped Porsche 962 C won the World Sports Prototype Championship. The Zuffenhausen-based automaker's Doppelkupplung also saw plenty of action in the Audi Sport Quattro S1.

Porsche designers and engineers began working on a powershift dual-clutch tranny with cam-disc mechanical control in 1964. Type 919 is how the company refers to said transmission. Rough shifting forced Porsche to cancel further development. However, the 1973 and 1979 energy crises prompted the Neunelfer's maker to revisit said concept. It's also worth noting that Porsche decided to pour money into developing a roadworthy dual-clutch box after the German Federal Ministry of Research and Technology organized a fuel economy-centric content.

Porsche successfully tested the PDK in a 924 back in 1981, meaning that it's older than both the Volkswagen brand's DSG for transverse applications and the Audi brand's S tronic for longitudinal applications. Before going any further, we should also talk about how DCTs work.

As opposed to motorsport-grade sequential transmissions and the automated manuals from the good ol' days, the dual-clutch transmission – obviously enough – features two clutches. You could even describe it as two manuals, for two separate driveshafts are controlled by two clutches. The first driveshaft is for odd gears (1, 3, 5, 7, and so forth), and the second is for even gears. When the driver puts a dual-clutch box into drive or manually selects first gear, the transmission also pre-selects the following gear.

Connected to its respective clutch but not to its respective driveshaft, second gear can be engaged within milliseconds. The shifting per se is most easily described as one clutch opening while the other closes, therefore resulting in stupidly quick upshifts. Downshifting is usually slower than upshifting because of engine and gear shaft speeds. The transmission and engine control modules collaborate to blip the throttle much quicker than you or I would, matching the crankshaft speed as required for downshifting.

Similar to a three-pedal manual, a double-clutch unit is much obliged to skip gears to the lowest possible ratio for maximum engine revolutions per minute. When you're cruising at motorway speeds with little in the way of pressure on the accelerator pedal, a DCT is programmed to shift into the highest gear available for improved fuel economy. If you ever heard the word mechatronics, it stands for mechatronic unit or module. This assembly brings together the hydro-mechanical whatnots of the transmission with the electronic control module of said transmission.

Advantages? Not having to reach for the gear lever during hard cornering, for example. Fuel economy is another strong point, with modern DCTs being more frugal compared to torque-converter automatics and even their much simpler three-pedal counterparts. Rev matching, quick shifts, no loss of torque when upshifting, and smooth shifts also need to be mentioned.

As for the downsides, complexity and maximum torque input open the list. Wet-clutch DCTs are marginally worse than stick-shift boxes in terms of mechanical efficiency. Dual-clutch transmissions also require pricier low-friction gear oil than manuals, and we also have to remember that more complexity results in more weight compared to an equivalent manual.

Now it's high time for us to delve into the world of Volkswagen Group dual-clutch transmissions. Of course, we'll kick this off with the Volkswagen brand's Direktschaltgetriebe.

Volkswagen DSG transmissions for transverse applications

The Wolfsburg-based automaker was riding high at the beginning of the 2000s, an era dominated by Ferdinand Porsche's second-most famous of grandsons after Ferdinand Alexander Porsche of 911 fame. You know, that Ferdinand Piech dude who pushed the Volkswagen Group into losing money on the Volkswagen Phaeton luxury sedan while reinventing Bugatti as a hypercar manufacturer with the Veyron. The early 2000s were also a good time for the Volkswagen Group in regard to build quality and reliability.

DSG is the short way of saying direct-shift gearbox, and the first production-intent DSG was the DQ250 of the fourth-generation Volkswagen Golf R32. Little did the company know back then, but the original R32 would pave the way for the R performance sub-brand. Unfortunately, the group's VR6 engine family has dwindled to a single member – the 2.5-liter EA390 – for the China-market Volkswagen Talagon, the slightly smaller Teramont, and the Audi Q6.

Following the 2003 Volkswagen Golf R32, the DQ250 would be adopted by the Audi TT 3.2 quattro and the New Beetle TDI. A wet-clutch design, the six-speed DQ250 is good for up 400 Nm or 295 pound-feet in the imperial system. The DQ250 is a six-speed design. Related to the original, the DQ200 arrived four years later with dry clutches and seven forward gears.

Not surprising in the least, saving a few euros by downgrading from wet clutches to a dry system resulted in plenty of problems. Compared to the DQ250, the DQ200 is an exclusively front-drive affair. Rated at 250 Nm or 184 pound-feet of maximum input torque, DQ200 is joined by the electrified DQ200e.

Volkswagen's 2013 Jetta Hybrid comes to mind, the brand's first hybrid with a lithium-ion battery. Volkswagen's first hybrid-electric vehicle intended for series production is the Touareg Hybrid, which combined a torque-converter automatic with a hybrid module featuring a NiMH battery pack.

Modern front-biased hybrids from Volkswagen come with the DQ400e, whose max torque rating is similar to that of the DQ250. Not exactly a coincidence, said transmission is a sixer as well. The DQ400e further stands out from other DSGs by means of three clutches housed in an oil bath. Two clutches are for shifting, whereas the third one is a disengagement clutch. As implied, it's responsible for disengaging the combustion engine from the transmission – when possible – to save dinosaur juice.

More powerful Volkswagens with a front bias, including the Mk7 Golf GTI, use the seven-speed DQ380. The DQ381 is a slightly improved version, with torque ratings of 420 Nm and up to 430 Nm (310 and 317 pound-feet), respectively. The DQ380 and DQ381 are trumped by a beefier transmission by the name of DQ500. Notable applications include B8-gen Volkswagen Passat BiTDI and the five-cylinder turbo Audi RS 3, which crank out 500 Nm or 369 pound-feet.

Volkswagen intended to launch a 10-speed tranny a few years ago, that DSG being the DQ511. Revealed with great pomp at the 2014 Innovation Workshop, the most complex DSG of the bunch was reportedly canned in 2015. The complexity, production costs, and the post-Dieselgate blow to the group's coffers had something to do with the canning. Two years later, the head of powertrain development officially confirmed its death. A drop-in alternative to seven-speed DSGs, the 10-speed unit was detailed by Volkswagen at the aforementioned symposium with 550 Nm (406 pound-feet) of maximum torque to its name.

Audi S tronic transmissions for longitudinal applications

Save for the now-discontinued R8, the Audi brand employs two distinct platforms for their combustion vehicles: MQB for transverse applications and MLB for longitudinally-mounted engines. The MLB is a bit of a weirdo because the entry-level A4 for European markets and the UK comes with front-wheel drive.

Have a wild guess for which vehicles the longitudinal S tronic dual-clutch transmission was developed. As far as Audi concerned, the answer is A4, A5, A6, A7, and Q5. It all started with the DL501 in 2008 with the first-generation Q5, which also came with six- and eight-speed tiptronic boxes. In Audi vernacular, tiptronic means torque-converter automatic. Ingolstadt's transverse dual-clutch tranny was originally called DSG, but not long after the introduction of the DQ250-equipped TT 3.2 quattro, it was renamed to S tronic.

It goes without saying that S tronic is currently used for both transverse- and longitudinal-engined vehicles with dual-clutch transmissions. The DL501 can support 550 Nm (406 pound-feet), whereas the newer DL382 goes to 500 Nm (369 pound-feet) of twist. Because the combustion-engined Porsche Macan is joined at the hip to the Audi Q5 on the MLB platform, its PDK-branded transmission is actually a seven-speed S tronic developed by Audi.

As you might have guessed by now, high-output models – including the punchy S4 and even punchier RS 4 – use torque-converter automatics from ZF Friedrichshafen. The list kicks off with the 8HP55 in the B8-gen A4 for North America, which is rated at 650 Nm (479 pound-feet). Really powerful models such as the V8-engined RS 7 and RS Q8 employ the 8HP95, for it supports 900 Nm (664 pound-feet).

The mid-engined R8 was initially offered with either a Graziano-developed manual or the R tronic automated manual, also from what used to be Graziano Trasmissioni before Dana purchased the company from Oerlikon back in 2019. Because dual-clutch trannies are far better than automated manuals in road cars, Audi eventually switched to the Graziano DL800.

Shared with the mechanically similar Lamborghini Huracan, the DL800 sits behind the naturally aspirated V10 we all know and love. Although the design layout of the 8-speed box in the V12-engined Revuelto was dictated by Lamborghini, said transmission is also supplied by Dana Graziano. With the Huracan on its way out, look forward to this new dual-clutch box in the V8-powered successor as well.

Porsche PDK transmissions

The PDK can trace its roots back to the Sportomatic, a semi-automatic transmission developed in collaboration with Fichtel & Sachs. Released in 1967, the Sportomatic is neither a torque-converter automatic – despite having a torque converter – nor a manual – despite having a clutch. A microswitch activates the vacuum-operated clutch through a solenoid when the gear lever is moved into the desired position, whereas the torque converter's role is to stop the vehicle without declutching or engaging neutral.

Sportomatic would be replaced by Tiptronic with a capitalized T versus tiptronic at Audi. You can think of it as a stopgap between the Sportomatic and the seven-speed PDK, with the 964-generation 911 being the first Porker to feature the torque-converter Tiptronic. The second phase of the 997-gen 911 replaced it with the PDK, which grew an extra gear for the 992.

Speaking of the 992 series, it can be had with both the seven-speed PDK and eight-speed PDK. They're supplied by ZF Friedrichshafen, which refers to said transmissions as 7DT for the first version and 8DT for the improved one.

The most powerful application to date for the 7DT is the Porsche 911 GT2 RS from the 991 series. The rear-engine and rear-drive thriller produces a manic 700 ps (690 hp) at 7,000 rpm and 750 Nm (553 pound-feet) at 2,500 rpm. The seven-speed Porsche Doppelkupplungsgetriebe was also used by the Panamera, which dropped the 7DT in favor of the 8DT for the second generation.

Manufactured at ZF's Brandenburg plant, the 8DT is optionally available with a hybrid module that originally rocked the following numbers: 100 kW of peak output (134 horsepower), 55 kW of continuous output (78 horsepower), and 400 Nm (542 pound-feet) of torque. In the third-generation Panamera, it makes 140 kW (188 horsepower) and 450 Nm (332 pound-feet). Top speed in electric mode? That would be 140 kilometers per hour (87 miles per hour), thank you!

On an ending note, is there a case to be made for a 10-speed transmission à la the DQ511 we covered earlier? Considering that Ford, General Motors, and the folks at Honda poured millions over millions of dollars and yen into torque-converter automatics with 10 forward ratios, there is a possibility that the Volkswagen Group will up the ante as well in due course, especially in the face of ever-stringent emission regulations in the EU and gas mileage regs in the US.