Gearbox issues; and problems at VW Service Centre

[Jellandross]

http://paultan.org/2014/03/17/dual-clutch-transmissions-dry-clutch/

 

 

Ah, the dual-clutch transmission.  There was once a time where upon hearing that a car was to be equipped with one, motorheads would speculate on whether it would deliver incredibly quick shift times made famous by Volkswagen’s DSG, enhancing a car’s ‘fun to drive’ factor.  Things have certainly changed since then – now when a car buyer hears that a car is equipped with an advanced dual-clutch transmission, they ask whether it is a wet clutch or dry clutch system and what the failure rate of the ‘box is.

 

Although we’ve heard of issues with both types of dual-clutch transmissions, it’s the general belief that dry clutch versions of the transmission are far more problematic.  Wet clutches run in an oil bath, and are generally used for higher torque applications, where there is more energy and heat to handle and the oil helps cool the gearbox down.  However, as a downside, wet clutch gearboxes have higher parasitic losses because the oil has to be pumped through the gearbox to cool the clutches.

 

As an example, in Malaysia the six-speed DSG in the Volkswagen Golf GTI as well as the seven-speed S-Tronic units in Audis are wet clutch units.  The last-generation Ford Focus TDCI, as well as the current Ford Mondeo and Ford S-MAX, also use wet clutch versions of dual-clutch transmission technology.  There’s of course the higher performance applications of the form, like Porsche’s PDK and as found on the likes of theBMW M3 and M5, Mercedes-Benz SLS AMG as well as the grey market Nissan GT-R.

Dry clutch transmissions are said to be more efficient because of the reduced volume of oil being pumped through the system.  This is because the torque capacity of these models are designed to be lower.  Volkswagen’s seven-speed gearbox – paired to its 1.4 litre TSI engines – is a dry clutch variant, and so are the dual-clutch gearboxes found on the current generation Ford Fiesta and Ford Focus.

Let’s make one thing clear – no car company intentionally puts out a product into the market that it doesn’t think will last the lifespan of the car.  The definition of lifespan is not forever of course, but an acceptable service lifespan that differs between manufacturers or products, usually at least 10 years onwards.  Technology is tested extensively with all kinds of use cases to try to identify and predict issues that might arise.

 

However, sometimes things slip through.  Swapping out additional cooling that was considered not needed in exchange for additional efficiency proved to have issues.  Last year, Volkswagen announced that it would be swapping the synthetic oil in its DQ200 seven-speed dry dual-clutch transmission with mineral oil – essentially, the switch was to rectify a problem where electric malfunctions could occur in the gearbox power supply if synthetic gearbox oil was used, particularly if the vehicle is subject to a hot and humid climate, coupled with a high proportion of stop & go driving.  Sounds like Malaysian roads for sure.  Recently, Fiat recalled 19,500 units of the Fiat 500L because of dry-clutch DCT issues, and Honda recalled over 80,000 cars that were fitted with its DCT gearbox.

 

Because of these issues, some gearbox manufacturers are already moving away from dry dual-clutch transmissions for entry level cars.  Getrag’s latest – the new 6DCT150 dual-clutch transmission – uses wet clutch technology instead of a dry clutch layout despite being an entry-level gearbox designed to handle loads of up to 170 Nm.  As a comparison, the older 6DCT250 currently found in the Fiesta and Focus is rated up to between 240 Nm to 280 Nm, and uses dry clutch technology.

 

According to Getrag CTO Didier Lexa in an interview with DrivelineNEWS.com, these small engines and dry clutch gearboxes are often coupled with relatively heavy vehicles.  When a small engine accelerates a large mass, the gearbox needs a longer synchronising time, which generates more heat.  And even when installed in small vehicles, the thermal constraints on these small cars (which have smaller engine bays) are even greater than on C-segment or D-segment cars.

 

So in the end, it looks like a wet clutch is needed not just for powerful sporty cars but small engines in big cars as well.  A dry clutch system only works well in an area in the middle of those two extremes; however, with advancements in oil pump technology, the difference in terms of efficiency between wet and dry clutch has been minimised.  So is there really a point for dry clutch technology now?

 

Indeed, Getrag’s recently announced dual-clutch products all use wet clutch technology – no dry clutch in sight.  Other than the new 6DCT150, there’s also a new seven-speed 7DCT300 and a hybrid 7HDT300, designed to pair a combustion engine with an electric motor.  However, the existing 6DCT250 will live on for another six to eight years before it is retired.

 

With these new learnings, car manufacturers should pick and choose wisely before deciding on which gearbox to implement.  For example, while Ford has opted to pair the Getrag PowerShift 6DCT250 with the1.0 litre Ecoboost engine in the Ford Fiesta, the same 1.0 litre Ecoboost unit is paired with a Ford-GM torque converter six-speed automatic, the 6F, in the larger Focus in Europe.  Volvo, a PowerShift user and which has a model line-up starting from C-segment (Focus-sized V40) onwards, has moved away from the 6DCT250, replacing it with an Aisin eight-speed torque converter auto in the latest generation of its cars.

 

Others are also trying to innovate dual-clutch transmissions in other ways.  Both GM and Honda are experimenting with dual-clutch transmissions that have a torque converter to help smoothen out stop-and-go situations.  Could that be the right path to work out the final few kinks from dual-clutch technology?

 

 

http://paultan.org/2014/03/17/dual-clutch-transmissions-dry-clutch/

 

in short, wet is better than dry. more shiok, less abrasion, less wear and tear. i thought we should all be well aware of this already. the engineers who invented the dry clutch must be all lacking in experience.

Edited April 25, 2016 by Jellandross

[Audi2016]

in short, wet is better than dry. more shiok, less abrasion, less wear and tear. i thought we should all be well aware of this already. the engineers who invented the dry clutch must be all lacking in experience.

 

They were so proud of this highly efficient and modern (at then) dual clutched (dry) transmission when it was just launched. It had won quite a few awards too.

 

But Europe cars have a very high proportions of manual transmissions vs DCT. And they don't have as much constant start stop traffic like we do in Singapore or some Asian countries. So reports of this problem is proportionately lesser and seem to be less than the reality of what we face here.

 

I got a new Scirocco for 4 years+ awhile ago. While the Mechatronic Unit in my dry 7 speeder failed me twice (both unable to start in the morning, tow away), I had no regrets.

 

Fun little car.

[Baal]

Is it still 9 in 10 bnb rides having 3 pedals in europe? Interesting new nAme coined. 'dry 7'.

[Ivantanjh]

Driving a mk5 Golf and just ordered a mk7 sportsvan.

 

My point being, every car has challenges and problem, VW isn't the only one, used to drive a Subaru Forester for 9 years and that has problem too, though it may not be he GB.

 

FYI, my mk5 mechatronic failed when she was 6 years old and had to spend 6k but she is a good and decent drive.

 

Like the world is not prefect, no car is prefect too, look at Honda vezel, it's make in Japan and Japanese are known in general for being a perfectionist.

 

My 2 c

[Fuelsaver]

Driving a mk5 Golf and just ordered a mk7 sportsvan.

 

My point being, every car has challenges and problem, VW isn't the only one, used to drive a Subaru Forester for 9 years and that has problem too, though it may not be he GB.

 

FYI, my mk5 mechatronic failed when she was 6 years old and had to spend 6k but she is a good and decent drive.

 

Like the world is not prefect, no car is prefect too, look at Honda vezel, it's make in Japan and Japanese are known in general for being a perfectionist.

 

My 2 c

good u n many others don't mind as long as gve u driving pleasure that can't b measure in $.

 

it's the other group that minded alot; i'm ready to replace wear n tear like shocks, mounts, bush, wheels but not a drivetrain component like engine or gb, not to mention being inconvenienced n need to haggle w AD / PI on warranty.

nobody perfect, even jap compromise qc at expense of technology / development.

thats y i bettin my chips on korean the new jap.

[Audi2016]

good u n many others don't mind as long as gve u driving pleasure that can't b measure in $.

 

it's the other group that minded alot; i'm ready to replace wear n tear like shocks, mounts, bush, wheels but not a drivetrain component like engine or gb, not to mention being inconvenienced n need to haggle w AD / PI on warranty.

nobody perfect, even jap compromise qc at expense of technology / development.

thats y i bettin my chips on korean the new jap.

 

Actually in my opinion, MU failure or gearbox replacement isn't a very expensive cost.. esp. when compared to the price of the entire car. When the car is out of warranty, an entirely new transmission replacement is $2000+ or so via 3rd party workshop. AD's cutthroat prices will be around $5000-$7000 inclusive of labour. After that, it buys you another 2-3 years of possible problem free gearbox experience.

 

What is actually more scary is premature engine haul due to piston crack.. Can happen before warranty ends, even so, it will cost you $12,000 for engine haul after AD offer you "good will" waiver of labour costs. But this issue more common for the twincharged models.. not the single turbocharged models.

 

That said, everyone's risk appetite is different. Some don't mind, some very particular. 

[Fuelsaver]

Actually in my opinion, MU failure or gearbox replacement isn't a very expensive cost.. esp. when compared to the price of the entire car. When the car is out of warranty, an entirely new transmission replacement is $2000+ or so via 3rd party workshop. AD's cutthroat prices will be around $5000-$7000 inclusive of labour. After that, it buys you another 2-3 years of possible problem free gearbox experience.

 

What is actually more scary is premature engine haul due to piston crack.. Can happen before warranty ends, even so, it will cost you $12,000 for engine haul after AD offer you "good will" waiver of labour costs. But this issue more common for the twincharged models.. not the single turbocharged models.

 

That said, everyone's risk appetite is different. Some don't mind, some very particular.

That y i nvr wanted to be inconvenienced due to such issue. Otherwise money will solve the rest of issues.

 

Really so cheap for brand new gb? My four speeder oso two k plus for brand new gb wo labor yet.

[Arch1984]

$2k plus sld be for MU only. The whole gearbox would be much more expensive.

[Keithchue]

the more I look at this thread, the more it lok scary for owning a VW. seems like we are penalised for choosing a VW over competition and we got the short end of the stick.

 

I hope my MU holds. and my pistons don't crack.

[Civic6228]

the more I look at this thread, the more it lok scary for owning a VW. seems like we are penalised for choosing a VW over competition and we got the short end of the stick.

 

I hope my MU holds. and my pistons don't crack.

 

I thought that you are looking at the Harrier ?

 

In my opinion, our local weather and driving style could be the reason with the failure of the DSG, too much "start/stop" driving.

 

I would rather not take the risk with the dry clutch for any model under VW.

[Ivantanjh]

I thought that you are looking at the Harrier ?

 

In my opinion, our local weather and driving style could be the reason with the failure of the DSG, too much "start/stop" driving.

 

I would rather not take the risk with the dry clutch for any model under VW.

 

Then probably taking public transports will be the best, didn't the MRT break down again.

[Fuelsaver]

Then probably taking public transports will be the best, didn't the MRT break down again.

Mrt breakdown not affecting our pockets directly, though inconvenience is frustrating.

[Ivantanjh]

Mrt breakdown not affecting our pockets directly, though inconvenience is frustrating.

 

True that, my point being, no car is prefect so just enjoy the moment.

[Civic6228]

True that, my point being, no car is prefect so just enjoy the moment.

 

True that too, no car prefect ..... but I would avoid the dry clutch and it has nothing to do with public transport.

 

Btw, this is a car forum.

[G1234]

Compared to today's prices, what I paid for our Passat was a lot closer to the Japanese brands back in 2008. In fact, it was cheaper than our original first choice (Mazda CX7) and 3rd choice (Ford Mondeo), both going for 120k then.

 

 

Why I'm still somewhat happy with my VW car

Other than a couple of batteries (once every 20 months or so), and some water & fuel pump replacements in the past year (after 3 year warranty), everything else actually works very well. Nothing electronic had ever failed (and there is a host of electronic "this" and auto "that") At idle, I can barely feel the engine vibration (can't say the same about my previous 2.0 Civic after just 6 months). There isn't even any creaking or groaning between the internal plastics and bodyshell of the car, and we're already approaching 100,000km.

 

That is why the gearbox is a niggling issue for me.

 

As I am one of the first 1.8TFSI Passat owners in Singapore, and with our rather high mileage, we know that they haven't had much experience dealing with this sort of thing (previous Passats had less Torque) and are also coming to grips with the DSG fiasco of later cars.

 

All I want for them is to acknowledge that the "no service requried" stance on the automatic transmission is a mistake and to make amends for that.

 

If not, I'm probably going on a witch hunt and gathering all the Passat owners who are encountering the same issue and get VW SG to do what VW USA did, which was to extend their warranty on the very same gearbox to 7 years/100,000 miles.

 

How is ur Passat? Any issue till now? 

[Presea]

Hi there....

For an 8 year old car with a rather aggressive driver, the issues will always be there.

 

Cat Convertor, Fuel Pump, Turbo parts... coolant parts... about 5K spent in the past year or so.
That also includes 2 rear door locks...

oddly enough, as my "new" Gearbox reaches 90k, and with a ATF servicing almost 60k ago, it is actually going very well.... just a little hard shifting from 2-3/3-2. Nothing like what I experiened 4 years ago.

But now, with the new parts... and even though I never "dynoed" it, the car accelerates even harder than I can remember, so if you see a Black B6 Passat doing crazy stuff on the road... it's just me... enjoying a newfound youthfulness.


More importantly, as I have not been going back to VW Service Center (I go to VAG East instead) I no longer have to wait for an appointment, or parts, or diagnostics. 2 weeks back, I drove there in the afternoon with a misfiring engine, and by evening, 4 new fuel pumps and a door lock fixed, I drove home.

I intend to keep the car beyond 10 years if the COE is low in 2 years time.

[Baal]

@Fels

 

what do you think of the EDC 6 dry that the Renault Fluence is using.

Since the car's torque is 240nm, I believe it should be on the Getrag EDC 6 Dry for up to 280nm.

 

Edited May 3, 2016 by Baal

[Baal]

Cat A BnB, imported as re-con (2nd hand) already ~2k.

 

Heard from Jetta owner brand new Dry 7  is ~8k from AD, all in.