I think a few of the car mags are running 2.0 TDI models with DSG as long termers, and I think both of them have experienced stalling. I didn't think this was possible with an auto?
DSG is not a conventional auto box with a fluid coupling.
It has two mechanical clutches instead:
www.moller.no/photoalbum/view/?size=org&id=1591
link:www.audiworld.com/news/02/tt32/content.shtml
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The DSG is a good but very complex system. Lots of things have to happen 'just right', with correct timing for it to work properly, so there is lots of scope for (expensive) problems. I tend to be very cautious when it comes to gearbox technology - from my experience a regular layshaft manual or an epicyclic-geared stepped-ratio automatic are the most reliable choices. Virtually every other gearbox technology that has been introduced (CVT of various types, sensotronic/selespeed, ACTS, toroidal transmissions etc etc) have suffered problems. I would not be keen to own a DSG out of warranty - not until it becomes much better proven.
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As I understand it, they build in some 'creep' so that it mimmicks a regular auto box. But to do this it must constantly slip the clutch, so surely if you drive it in traffic like a regular auto, for extended periods, then won't the clutch(es) suffer?. In a manual you'd tend to move up the queue a little, then dip the clutch, rather than constantly creeping along riding the clutch.
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I have had a 2.0TDI DSG "stall" on me. It seems like an engine management/gearbox conflict. Only had it happen on 8P4A chassis Audi A3 though (that's a 2004 model year car)... the 8P5A (2005 chassis) cars have all behaved fine. Our Touran has also similarly behaved itself (also a 2005 chassis). In traffic the gearbox doesn't slip the clutch, rather like a diesel manual car the vehicle creeps at idle speed in first gear, you can discern the clutch pattern as you move off fairly well and I can assure you it doesn't slip when creeping.
Chris
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In traffic the gearbox doesn't slip the clutch, rather like a diesel manual car the vehicle creeps at idle speed in first gear, you can discern the clutch pattern as you move off fairly well and I can assure you it doesn't slip when creeping. Chris
Eh? How does it 'creep' if the clutch is not partially engaged (slipping) then? Don't understand what you mean about Diesel manual cars either.
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Thanks for the above comments. Given we only get manufacturer's warranty (two years) here, and extended warranties do not seem to be available, this needs further thought. Cheers.
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I was recently in the local audi dealer collecting some parts. The service advisor had stupidly left some 'confidential' bulletins lying about on the desk, concerning different faults with DSG. There were at least 10 possible faults that could occur, the pile of bulletins was about 1cm thick. I made a smart ass remark about these boxes being unreliable and pointed to the paperwork. The advisor got rather shirty and hurriedly removed the papers from public view!
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In a manual diesel car it is possible to bring the clutch up fully so that the drive is engaged. The car "creeps" forwards at the minimum forward speed e.g. if first gear is 8mph/1000rpm and the idle speed is 750rpm then the car creeps at 6mph. The DSG is the same, the minimum forward speed of the vehicle is what it creeps at. The engine management system in a modern car is programmed not to allow the engine speed to fall below the preset idle, as a result the additional load of moving the vehicle is compensated for.
Creeping in a Torque convertor based automatic similarly is representative of the idle speed of the car i.e. faster idle faster creep, but also of the amount of torque imparted by the engine as torque is transmitted better than RPM by a fluid flywheel. To give the same feel as an automatic (VAG classify the DSG internally as a manual gearbox as it has clutches) the clutches on a DSG begin to engage as you release the pressure on the brakes. You can feel this best by engaging drive with the handbrake on. You feel the car pull for a couple of seconds against the brake and then it desists and drops to neutral. Now take the handbrake off sharply and you feel the momentary clutch slip as the gearbox engages drive. This is less evident if you hold it on the foot brake as the drive is much more "ready" to engage. The programming appears to only "drop" the clutch rather than disengage the gears.
Chris
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Eh? How does it 'creep' if the clutch is not partially engaged (slipping) then? Don't understand what you mean about Diesel manual cars either.
Think he refers to the diesel's capacity, engine at idle and feet off everything, to creep in first gear at walking pace plus. Maybe petrol cars with electronic engine management will do the same, but the last one i drove had a carburretor and certainly would not.
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So if the minimum 'creep' speed is 6mph @ 750rpm, then what happens if you apply the brakes because you only want it to creep at 3mph. Doesn't it then have to slip the clutch? There's many occasions when my auto cars go to fast in traffic with no gas applied, so then I regulate it with the brakes to get anything between 0mph amd whatever it will do without the brakes, say 5mph.
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Fully engaging a clutch at engine idle (about 8mph) is not creep as I would understand it. Creep on a regular auto means being able to inch slowly forward by easing on and off the brakes. If you are travelling forward in a DSG and apply the brakes then there must be an operating regime where the clutch is slipping - otherwise the car would lurch to a sudden halt as you apply the brakes.
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Leaving aside that I can't see a need to "creep" that slowly I did an experiment in the Touran this morning to see what happens. In traffic I have always kept a little room in front of me and crept "feet off" in 1st as long as I can to void excessive clutching/braking.
1. Speed with feet off pedals is ~5mph in the Touran 2.0TDI DSG, slightly less than is in my (manual) A3 where it moves around 8mph at idle
2. If you brake gently to reduce the speed below that the car pulls against the brakes and then drops the clutch in the DSG just before the vehicle is about to halt. If you are careful with your brake pressure you can just about pick up the point where the clutch begins to drop, and if you release the brake at that point you can feel the clutch coming back up to regain the idle creep.
Hope thats of some use
chris
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