At the bottom are some
review videos of the DSG. To differentiate between the
DSG and a conventional planetary gear-torque
converter automatic transmission, I'll call the conventional auto a slushbox.
Tiptronic is a term used by VW and Audi and only refers to a non-manual transmission
that lets you shift the gears with the shifter.
Below is a cutaway showing the manual transmission type gears and
dual clutch system of the DSG.
VW's direct shift gearbox (DSG) is a 6 speed dual clutch manual-like transmission that automatically shifts. It has internals similar to a manual transmission with a "brain/valve body" called mechatronics which shifts it. Depending on the model, VW/Audi and Borg Warner currently make DSG transmissions. It's better than a conventional automatic transmission and great on turbo cars because the more consistent power delivery keeps the turbo spooled up. The main disadvantage vs. traditional manual transmission is that it's harder to modify and heavier. The fluid and filter should be changed every 40,000 miles. (also see How to change your DSG or S-tronic fluid) As of 2011, VW Auto Group has made around 3.5 million DSG transmissions. Almost all are made in Kassel, Germany with a few made in Dalian, China.
The DSG was first introduced to the US in 2003 with the model year 2004 New Beetle TDI and Audi TT. The gasoline NB still used a slushbox for that year. 5th generation VW Jetta TDI starting in 2005.5 also got DSG. Premium trim cars equipped with slushboxes had a rolling change to DSG across the VW model line over the years. If the car is premium trim, it should have a DSG. Base cars usually still come with a slushbox.
Steering wheel paddle shifters for TDI with DSG were introduced in 2010 but you can retrofit them to earlier 5th generation cars and new 6th generation cars, see 1000q: paddle shifter steering wheel retrofit for more details. The stock gear selector looks like a normal automatic gear selector with "park, drive, sport, etc." and a tiptronic position. All DSG cars should have a DSG badge on the gear selector. Pictured right is an example from a 2004 New Beetle highlighting the badge. The gear selector has PRND positions just like an auto slushbox. S is sport mode and the +/- position is the tiptronic position. Both DSG and slushbox may have the tiptronic position.
Some have said that the DSG transmission learns your driving style but this is technically incorrect. The DSG transmission shift behavior adapts to variables like internal wear, D or S mode, and other input factors like throttle position and rate of change, uphill or downhill, and applies these variables over an existing shift map. Learning is the wrong term since it means new knowledge that wasn't there before- the transmission cannot learn anything new, it just applyies variables to existing maps. Some engineer has already determined and tested how the shift maps and variables will react. There is no single input field "driving style". The perception of a reaction to driving style is the result of the change in a number of variables applied to the shift maps. So yes the transmission adapts but not how most people think. Although "learn" might be used in marketing literature, it's not the right word to use when describing technical operation.
This article focuses on the 6 speed DSG found in North America but there are also 7 speed DSG for front wheel drive (transverse layout) and longitudinal DSG for rear wheel drive.. The 7 speed transverse DSG isn't available in North America because it's limited to 184 lb-ft of torque and we don't have the low output engines. The biggest difference in the 7 speed is the extra gear and the dry clutch vs a wet clutch. More gears and the dry clutch should give greater performance and fuel economy but dry clutches aren't cooled by fluid and could have limits on launch mode. The torque limit means it won't appear on US TDI engines anytime soon. In any case, TDI have such a wide torque band that a 6 speed DSG is more than sufficient to work very well.
Here is a video showing how the Porsche PDK (Porsche Doppel Kupplungen, Porsche
double klutch) dual clutch transmission works. Even though ZF and
Porsche developed PDK independently from the Borg Warner developed DSG / S-tronic, the video explanation
works for both. There are also dual clutch shift type
transmissions from Mitsubishi (made by Getrag) with other manufacturers
A DSG is a great transmission compared to a slushbox. If you leave it in automatic mode, it's identical in ease of use. It's lighter and has less parasitic power loss. You should also notice faster shifting and better fuel economy than a slushbox. A DSG can also deliver better car performance and smoother shifting than a manual transmission. In fact, the newest generation of high performance sport cars are faster when equipped with dual clutch transmissions, everything else being equal. Since the mechanism never misses a shift and the clutches are almost always engaged, DSG give more consistent power delivery, especially in turbo cars. In a manual transmission turbo car, you normally lift off the throttle during shifts to rev match the engine, interrupting power delivery. Because a DSG only has a tiny gap in power delivery, the engine is kept under load which keeps the turbo spooled up. The DSG also eliminates driver inconsistency in performance shifting.
A DSG is also good for drivers with knee problems or family members who don't want a manual (or you can't stand their shifting)! There are some some quirks with a DSG and these are discussed in further detail below.
Despite these advantages, I still feel that a manual transmission is better for a skilled driver who doesn't mind shifting. If nothing else, a manual transmission gives the driver the ability to maximize the fuel economy which is one of the strongest points of a TDI. It also costs less and is more tolerant of higher level power upgrades or poor maintenance. A DSG needs consistent fluid changes every 40,000 miles. See this FAQ article on how to do this 1000q: DSG DIY fluid change. Conventional manual transmission gear oil can go anywhere between 60-100,000 under normal use. Many independent garages and even some dealerships are not experienced with the service requirements of the DSG because it's still relatively new. A DSG will also not let you rev to engine redline because it will force a shift slightly below redline.
Some other disadvantages of a DSG are potentially lower reliability, higher replacement costs, and heavier weight compared to a manual. In theory, the DSG on the TDI should give better performance but the increased weight and greater parasitic power loss take away performance compared to a manual. The clutches in a DSG are lubricated in fluid and this creates greater parasitic losses than a dry clutch. So far, the real world difference in performance between manual and DSG (when mated to the VW/Audi 4 cylinder gas/diesel engines) isn't statistically significant and is well within variations in driver, environment, tires, and engines.
While the DSG's official limit is 258 lb-ft (350 nm) of torque, it's possible for the transmission to hold more power. Stock torque on a TDI engine is 170-236 lb-ft, depending on the engine. HPA motorsports built some high power testers for VW and they experienced no unusual problems. They recommend fluid changes every 10,000 miles on high power modified cars. And of course, how much you actually use that available power and towing/racing use will effect transmission and fluid longevity. If you have a TDI, the ECU has a torque limiter so that any power upgrades will not go over the DSG limit. To gain the full benefit of power upgrades you may need a DSG tune. Malone tuning offers DSG tunes for 2009+ cars along with power upgrades.
If you want huge power gains, you may also need a new clutch pack. While a conventional manual transmission clutch can be changed without too much difficulty, there aren't too many places to find and install DSG clutches.
The new 7 speed DSG used on the Audi S5 can hold up to 406 lb-ft but it's used with a longitudinal engine, not the transaxle used on the 4 cylinder TDI. The new 7 speed DSG on the Euro Golf/plus is for small output engines and is limited to 184 lb-ft.
A DSG transmission is a great piece of technology but it's still relatively new compare to a manual transmission. Because of this, a factory extended warranty could cover any potential problems that won't show up until some miles and age have accumulated on the car. I would rather put aside a general emergency fund for home/auto/health repairs, but it's an option. Just carefully read what an extended warranty covers and terms because the contracts are often worded to exclude many repairs, certain "wear parts", or exclude items which don't have a strict maintenance history!
Below are some of the more common problems reported. If you do report a drivability or safety problem to the dealer, some will tell you to keep driving it because the part is on backorder. If the car has a drivability or safety issue, demand a loaner car or rental car and file a report with the NHTSA. Driving an unsafe or defective car is unwise and this can be a dealer trick to avoid lemon law criteria in some states.
Recent update: VW has extended the warranty on all DSG or S-tronic transmission for 10 years/100,000 miles, transferable to subsequent owners for 2006-2009 model years. This covers the R32, Jetta, GTI, Eos, and Audi TT and A3 and only applies to a "limited production range", whatever that means. It's unrelated to the recall mentioned below. To see if your past repair or current car is covered you have to call the VW loyalty center at 1-800-444-8982. A .pdf copy of the warranty extension for DSG transmission letter that was sent to owners is to the right.
The National highway transportation safety administration (NHTSA) recently opened an investigation on power loss and jerky power delivery of the DSG. While the number of DSG with problems is small, the problems reported which opened the investigation are serious and could result in a crash. This investigation is not limited to TDI, it's for all VW/Audi DSG. The NHTSA action number is PE09035 opened July 17, 2009 and currently covers 2008-2009 models.
While some DSG have a small delay in clutch engagement and power delivery from a full stop, this is considered normal and can be expected and compensated for by the driver. The more serious problems involve false neutrals for no reason, shifting into neutral by itself, and not being able to shift back into drive from neutral while at speed. These sorts of problems are not unique to DSG transmissions or VW since they can occur on any car with a defective part or faulty design. However, there are many more anecdotal problems reported than just the cases which resulted in the opening of the investigation. Ultimately, the opening of an investigation means only that there are problems reported which merit further investigation and this should currently be the only conclusion which one should draw from this action.
On Aug 2009, VW started a recall on 2009 and 2010 DSG on the temperature sensor.
Models affected are built between August and September 2009. A faulty temperature sensor
can result in illuminated warning lamps in the dashboard and the transmission may shift into neutral.
It appears that both sensors below are in the same assembly. This is
probably responsible for some of the flashing "PRNDS shift light" incidents. Below
are some descriptions of the temperature and rpm sensor.
battery (also check voltage regulator or alternator) can cause flashing PRND or
PRNDS lights and DSG shifting problems. If you get the blinking
shifter PRND PRNDS light and false neutrals (transmission shifts into neutral by
itself) then you could have a bad transmission temperature sensor as mentioned
above. Here is an example of a stuck
neutral on a 2009 Jetta TDI and a similar problem on a 2007 Audi A3.
Other common issues showing up are DMF or mechatronics problems.
Mechatronics houses all but 2 sensors in the DSG transmission and all external input signals for controlling the transmission go to it. There are also pressure control valves and solenoids that control shifting. The individual parts are not yet serviceable separately. It's designed to be replaced as a unit and the retail price is in the thousands of dollars! A brand new DSG transmission costs about $5,500! Used transmissions from an auto recycler are currently the only economical option. So far, there have been over 1 million DSG units made so the price should go down over time. Here is a video showing removal of mechatronics. It's in German but you can figure out what's happening.
The advantage of a DMF is smoother power delivery and less noise, vibration, harshness. But because it's two parts instead of one, it can fail, and has failed at higher than expected rates on DSG. A slipping belt chirp, soft grinding, poor shifting, or metallic rattling at idle noise may be indicative of a failing DMF. There is something about early DMF flywheels on the VW DSG that has proven to be not durable. A few DMF even liberated themselves from the transmission with spectacular results and as a result, all newer DMF were redesigned. The oldest part number was 03g 105 266 r, followed by a newer one with suffix "ap". The newest part number has suffix "be" (03g 105 266 be) and should fix this issue. Here's a source for new flywheels: www.dieselgeek.com. For more on how to read VW part numbers, see 1000q: part numbers and ETKA explained. For more on flywheels and other clutch and manual transmission FAQ, see 1000q: TDI clutch FAQ.
Below is a picture of a DMF from a 2006 DSG
transmission. DMF on DSG vs. manual transmission are different. The grease was cleaned out and the flywheel was split
open. You can see the dampening springs and stops. Cars equipped with the old part are mostly out of
warranty. DMF were actually recalled in
Australia but not in the US so if you have a problem, report it to the NTHSA
and maybe something might happen. I'm not sure if the DMF part number was the
same but the recalled part was on the Australian 2.0L 138hp/236lb-ft torque
engine instead of the older, lower torque US engine. If you have a manual transmission there was a TSB for defective
clutches, see the clutch FAQ for more details on the manual transmission clutch
The DSG transmission needs to have consistent maintenance. Every 40,000 miles the DSG fluid and filter should be changed. The estimated price of this service is about $400-900 at the dealer or under $150 if you do it yourself. See this article if you wish to DIY change: 1000q: How to drain and refill the DSG transmission fluid. Fluid capacity is about 7 liters on a dry transmission, refer to your owners handbook for the exact amount and fluid spec. If used in a high performance or racing environment, shorten the fluid change interval as needed.
If you live at high altitude and cold temperatures (for example, 15oF), you may encounter a no start/hard start engine under extreme conditions with the TDI engine and DSG. This is not due to cold temperatures only or high altitude only. When cold temperatures are combined with high pressure altitude, the air is too thin and compression of the engine too low to overcome the resistance of the transmission, resulting in a no start/hard start. This is because a TDI engine runs off compression and these conditions, combined with the resistance of the transmission, are too much for the engine to start. A well maintained diesel keeps good compression for a long time but improper engine oil or engine abuse could cause loss of compression and make the no start problem worse. This issue does not apply to gasoline engines and manual transmission TDI don't seem to be as affected. There is at least one person who claims that on cold days in high Colorado, their TDI had a total no start problem and later got a settlement out of VW because of this known design flaw. If you live at a lower altitude or have warmer temperatures, you will not see this exact problem. If you live at high altitude or cold temperatures, a garage or an engine heater should help prevent this condition. Most Canadian TDI have standard engine heaters, US VW TDI do not (Audi A3 TDI does). If you need an engine heater, you can install one yourself for about $120 and a few hours work.
While a DSG is very similar in operation to a slushbox, there are a few differences. First, always set the parking brake before you put it in park (you should always do this on any VW/Audi since it sets the rear brake caliper self ratcheting mechanism and avoids stressing the parking gear pawl/shifter). Always press on the brakes before starting the engine (you should already be doing this with any car). The car could slightly lurch forward if you start the engine without the parking brake or brakes on. This condition is most likely under cold temperatures due to the viscosity of the DSG fluid transferring some motion from the engine to the transmission. Unlike a slushbox, if you take your foot off the brake, the car will not inch forward. When coasting with your foot off the gas you'll experience engine braking, just like a manual transmission. However, the transmission will downshift as you slow down. With a manual transmission, I prefer to do a combination of downshifting and neutral depending on the conditions. When stopped on a hill, the car may roll back a little if you don't apply throttle, just like a manual transmission. Most later DSG have a hill holder which holds the brakes until you step on the gas.
The dual clutch system tries to predict your shifting but it is not adaptive off driving style. It will adapt to adjust for internal wear to keep the behavior of the transmission consistent. This is verified by DSG transmission tuners.
To maximize fuel economy, shift the DSG manually. There are other advantages to a DSG transmission so don't feel like you are "wasting" the additional cost of the DSG by shifting manually. Drivers trying to maximize fuel economy report the average DSG mileage about 3-5 mpg average lower than a manual transmission. As an example, if you drive 12,000 miles/year and diesel is $4/gallon, this is only a difference of about $12/month, so don't be discouraged by the small difference. Although some of this difference can be attributed to build variation between cars, driving style, and fuel quality, the general opinion is that DSG will give slightly lower mileage than a conventional manual, everything else being equal.
The basic 4 cylinder transverse DSG transmission uses the same technology as the Nissan GTR's twin clutch or Audi S5 S-tronic. The GTR is a rear transaxle AWD DualTronic transmission by Borg Warner and the Audi S5 S-tronic longitudinal transmission is built by VW in Kassel, Germany, but they all use the same principles. The difference between DSG and other automatic transmissions which let you manually shift is how the mechanisms work. The internals of DSG are absolutely nothing like BMW's SMG or Nissan's CVT manumatic/"gearless" autos, etc..
All VW and Audi DSG on TDI in North America are transverse 6 speed transaxles. There is a 7 speed transverse DSG w/dry clutches but it's used on low torque applications (184 lb ft limit) which will only see use on small engine Euro VW/Audi. There is a 7 speed longitudinal DSG for Audi but it's only for cars that use a larger engine (with a higher power rating of 406 lb ft) with a longitudinal transmission. The DSG internals resemble a conventional manual transmission in that it uses gears and input/output shafts and clutches. A slushbox uses a planetary gearset. The dual clutch DSG transmission is almost like two 3 speed manual transmissions. In the 6 most common DSG, one clutch drives gears 1, 3, 5, and reverse. The other clutch drives gears 2, 4, and 6. Each concentric clutch is connected to its own input shaft. One smaller input shaft spins inside the other which is hollow. Each input shaft then has its own output shaft. This is why DSG have two final drive ratios listed. Output shaft 1 drives gears 1, 2, 3, and 4. Output shaft 2 drives gears 5, 6, and reverse. Therefore, one final drive is for 4th gear and one is for 6th gear.
The reason why the transmission can shift so fast is because mechatronics preselects the next predicted gear while you are still in the current gear. In other words, while one gearset/clutch is being used, the other is being preselected. See the videos on this page to see this in action. When you shift, all it has to do is release one clutch while engaging the other. It preselects the gear by taking readings from various sensors and decides what gear you are going to need next. At all times, while you are using one gear/clutch, the other gear/clutch is waiting to take over. The only drawback is that there's an awkward delay if you select a gear which has not been preselected.
As mentioned above in the summary, performance should be better with a DSG. The faster shifting and the elimination of driver variables delivers more consistent performance. The ability of the dual clutches to keep a turbo spooled due to the consistent power delivery also maximizes the ability of a turbocharged car. With high performance cars, driver ability becomes the main variable in consistent performance. DSG reduces the number of variables and lets the average driver achieve consistent performance numbers. Ultimately, the extra weight and greater parasitic power losses of the DSG are about equal to the increased performance, according to driver reports in VW Audi turbo cars. Any large difference in performance is due more to local environmental conditions, driver technique, and build variation between cars than to the DSG.
Here are a few more differences between a manual transmission and DSG:
-A conventional manual uses a single dry clutch, the 6 speed transverse DSG uses twin clutches lubricated with oil. The new 7 speed transverse uses a dry clutch.
-A manual does not use a separate gear oil cooler, the DSG uses a small fluid radiator cooled by the coolant. Because of this, a manual transmission TDI uses coolant glow plugs to help warm the coolant on cold starts, DSG does not since the DSG radiator helps warm it.
-A manual has no filter, a DSG uses a filter that should be changed every 40,000 miles.
-Lubrication in a manual is from the gear oil being flung around by the gears, DSG uses a fluid pump.
-The below pictures show a cutaway of the front and back of the DSG. Below are some descriptions of some visible components.
-The mechatronics is an electro hydraulic controller analogous to a slushbox valve body in that it controls and distributes fluid pressure to the various parts of the transmission. This is the "brain" of the DSG. By rerouting hydraulic fluid (the transmission fluid), it moves the shifter forks, which shifts the gears, and engages/disengages the wet plate clutches.
-The transmission fluid cooler is a radiator which uses engine coolant to control the temperature of the transmission fluid.
Click to enlarge the thumbnails.
More mechatronic pictures. You can see the various
solenoids and sensors and the electrical connectors which control the flow of
hydraulic fluid to the shifter and clutches. It is designed to be replaced
as a unit and is not yet serviceable by individual owners.
Pictured below is the dual clutch system. Hydraulic fluid pressure controlled by the mechatronic engages and disengages the clutches. Each set of clutches drives its own input shaft and gearset.
When modifying the clutch plates for a set which can hold more torque, the
clutch set is changed out. Pictured below are some various kits from HPA motorsports.
Cutaway of a DSG transmission shifting
German language video of the new 7 speed DSG
Do you have any questions about the DSG recall, false neutral, or stalling on your Volkswagen because of the automatic transmission? Please share your experience in the myturbodiesel.com forums. You can also search myturbodiesel.com here: