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I have seen many recent car launches in my home country which claim to have something called as an AMT or Automated Manual Transmission.

I am curious to know how is this different from a traditional manual transmission (ignore the CVT , i know how that works).

What is the purpose/advantages of the AMT over the DSG and traditional type.

What category does the DSG from Volkswagen group come into.

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Automated manual transmission is a kind of semi automatic transmission. The actual gear box will similar to the ones that you find in manual transmission, however the clutch control and gear shifting is automated. Mercedes had an AMT called sequentronic.

Direct shift transmission (getriebe in German) has two intermediate shafts with alternate gears (one shaft has gears 1,3,5 and the other one has 2,4,6,R). In DSG, the next gear is preselected. There are two dry clutches, one for each intermediate shaft, and during gear shifting one clutch is engaged and another disengaged. VW uses DSG and Ford calls them DCT (dual clutch transmission).

Neither of the transmissions above have a planetary gear box or a torque converter, which are standard in a conventional automatic transmission.

  • Why do we prefer the AMT over the traditional one? updated the question. – Shobin P May 27 '15 at 11:45
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    I think the biggest advantage to an AMT is increased efficiency. There is no slippage at lower speeds like with a torque converter. Manual transmissions are typically stronger and can transfer more power than automatics, but I don't know if that's a factor with AMTs, which I would guess are engineered to favor weight savings over strength. They're probably lighter, too, but that's just a guess. – TMN May 27 '15 at 14:46
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    Torque converters transmit motive force via a liquid. There are much greater losses via this liquid than via a dry clutch (something like 10% of the energy is loss going through a torque converter). – Aron May 27 '15 at 15:52
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    AMT is preferred because it offers the comfort and convenience of an automatic transmission(nonoperation of clutch & engaging gears) at a lesser cost. – knocksAndMisfires May 27 '15 at 17:16
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To follow on from knocksAndMisfires' answer and your question update...

DSG is a kind of AMT, in that the computer controls the actual changing of gears.

To my mind there are a number of differences between AMTs and traditional transmissions - some are obvious advantages, but are offset by other disadvantages...

  • Quicker gear changes - the computer can shift clutches in a fraction of a second - this means the headline 0-60 times can be a lot quicker, and the car feels more sporty to the driver.

  • Auto and manual modes - you can leave it in auto for dull town driving, and switch to manual on the open road, or when overtaking etc - so the 'best of both worlds' compared to a normal transmission.

  • 'Flappy Paddle' gearchange - makes it feel more like a racing car and means you have to take your hands off the wheel less.

  • More complicated - an obvious disadvantage - more to go wrong, and more expensive to fix when it does!

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    Thank you for the details :-) BTW i read "Flappy Paddle" in Jeremy clarkson's voice.. ... – Shobin P May 27 '15 at 13:10

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