[rajivr1612]

Originally Posted by Chethan B G

AMT is rudimentary. A stop-gap arrangement or a low-cost alternative. Works as intended, but the target application is different. Let us keep it aside for the time being.

Companies have to figure out a way to make them more rugged and reliable. Fact that the cost factor is always at the back of the mind, does not help researchers.

I have absolutely no experience with automatics hence not voting in the poll. With regards to AMT, from what I read here, there are neatly implemented ones like in the Tiago and Ignis. Yes, the majority of them are jerky but if the above couple of models could iron it out then the others can too.
Regarding your statement about DSG that "companies have to figure out a way..." why can't the same be applicable to AMTs as well? Why can't we give the same leeway for the companies to make it smoother.

[Guna]

Originally Posted by Hayek

I realised torque converters can be better when I drove the Vento with a 6 speed gearbox. And the fantastic shifting of the ZF 8 speed won the battle for the best transmission in my mind.

Current Ventos are DSG. Did it come with TC earlier?

[DrSumit]

Originally Posted by GTO

Give me a reliable & well-tuned torque-converter over an unreliable DSG any which day.

My only question, GTO, is - which regular car on our streets would plaster a smile on your face?

Voted for the DSG despite its reported unreliability, for I feel a smile on most days of the year is worth the probability of an occasional hiccup. Of course, since my experience with the DSG is on the Vento TSI, you could say that a good part of the driving experience is attributable to the engine.

[Lambydude]

Bought a grand i10 automatic recently after test driving most of the automatic hatchbacks available in the market now. My observations are
1. CVT - boring
2. AMT - jerky gear shift & Head bobbing. All AMTs have these issues including the much hyped IGNIS and Tiago
3. TC - smooth gear shift but low fuel efficiency
4. DSG - The best of the lot. I feel that the much maligned reliability issue is just a myth now. Have lot of examples within friends and family. None of them faced any reliability issues in the past 3-4 years.

[Hayek]

Originally Posted by Guna

Current Ventos are DSG. Did it come with TC earlier?

Yes, the Vento Petrol AT used to be a 1.6 l NA engine with a 6 speed torque converter. I think the same configuration is still used in the Rapid. They shifted to the DSG for the Vento when they moved to the 1.2 TSI engine. (OT)

[shashanka]

Originally Posted by Hayek

.....As for AMTs, I am not even sure they should be called automatic transmission (actually they aren’t)....

I agree Hayek - an AMT is not really an automatic transmission. It is an automatic 'engagement & dis-engagement' mechanism for a mechanical clutch - thus relieving one's knee of the pain in b-to-b traffic! And this is the endearing part of the system - it is essentially a manual transmission and at the same time it relieves your left leg/knee of constantly riding/using the clutch in normal traffic & the painful misery in b-to-b traffic!

And compared to all the high-tech gobble-de-gook of TCs, DCTs & CVTs (with their churning hyd. oil & infinitely variable belts/pulleys!) there are so few additional components to go wrong.

In fact there are several component mfrs. who earlier offered retro-fitting of the automatic clutch mechanism on popular existing cars to convert from manual to automatic - of sorts!

One need not go to such extremes, but the operating principle is sound & - contrary to popular assumption - the AMT is perfectly capable of handling shaft torque upto 500+ Nm and beyond.

For my money, the AMT is the way ahead. And the rate at which the mechanism is being refined (the clutch engage/disengage algorithm) and developed, there is no reason for it not to succeed.

[nishsingh]

I am not sure if this is true for any other Automatic Transmission, but the good ol' Torque Convertor on my wife's Ertiga has some degree of hill-hold, preventing the car from rolling backwards in mild to normal inclines. If true, this is a major advantage of the Torque Convertor over other Automatic Transmissions.

[Rahul Rao]

I voted for the Torque Converter, even though the only Automatic I own is a dual Clutch.
Torque converters have been there for a long time, and have improved considerably over the ages. Those coupled with small engines are not effecient, but with mid sized engines the effeciency drop is noticable only in bumper to bumper traffic.
A mid sized SUV like XUV500 or an Hexa with 6 speed TC can give you the acceleration surge when you torque up the system, and also decent effeciency on highway cruises.
Smaller crossovers like Creta, and now the same transmission with the Verna also performs beautifully.

Rahul

Rahul

[itwasntme]

Voted for DSG. After driving Honda & Renault's TCs, Toyota's CVT and Mercedes's TC, I find the VAG DSG (7 speed dry clutch) to be sublime!

[shashanka]

Originally Posted by Chethan B G

AMT is rudimentary. A stop-gap arrangement or a low-cost alternative. Works as intended, but the target application is different. Let us keep it aside for the time being.
IMO, Between the other three, the major difference in terms of power transfer is "Mechanical Isolation". TC's and CVT's provide mechanical isolation between the Engine and the Transmission / distribution system. In case of a DSG, there is no isolation.That makes DSG's complicated to design, as they handle the load all the time and under all circumstances. They are practically sandwiched between the engine and the distribution system.
TC's and CVT's are more reliable due to this very fact. Recent TC's and CVT's are very fuel efficient too. My pick as on date would be a TC followed by a distance by CVT. TCs because they are faster, perceivable, rugged and cheaper to maintain.
My thoughts are that the DSGs are the future for automatics. There is no transfer loss, but just that they lag a bit to begin with. Companies have to figure out a way to make them more rugged and reliable. Fact that the cost factor is always at the back of the mind, does not help researchers.

I see that you have no issues giving a long rope to the DCT contingent where research & development is concerned ("a way to make more rugged & reliable" re. the DSG).

The TC has been around since the 30's and has thus had a leisurely gestation period of 80+ years to get where they are today (not totally niggle free yet, mind you).

The CVT was introduced by the Dutch firm DAF (now defunct) in 1959 and apparently even earlier in the 1920's by the British firm Clyno (whose records are sketchy).

Thus both the TC & the CVT have had a long innings to get where they are - and all credit to them, certainly.

The DCT has a more contemporary history with the 2003 VW Golf Mk4 R32 being the first series production. So one can say that it is still 'work in progress' and companies have to figure out "a way to make more rugged & reliable".

In that case why not extend the same courtesy to the AMT as well?

And as for terming the AMT "rudimentary" & "stop gap" - well, that's a riot! The Ferrari Mondial had this transmission in 1992.
The Lancia rally team used the AMT (it was called the Valeo ECM - for electro-mechanical actuator for the clutch) in the Lancia Delta HF Integrale 4X4 which dominated the WRC scene in the 80's - 90's.

And today we have the AMT in our humble Celerios, Nexons & KUV100 as well.

So I'd say take a breather and give everyone a chance.

[Chethan B G]

Apologies if I have hurt sentiments. Intention was definitely not that.

This debate / poll being as on date, with the available technology we have in the market, I think today's AMT's do not stand a chance to be compared / pitted against the other ATs. It is unfair too. AMTs today are just automated clutch with sequential shifting of gears through actuators. I myself own an Alto-AMT. I know that there are far better ones in the market; but still.

If DSGs were as reliable as TCs, if not better, my vote would have been for the DSGs without doubt. But, as on today, they are not. That holds the key.

This is an open discussion / poll. Each one can air his / her opinion. I have aired my personal opinion. I may be wrong. But that is what I know from my experience and it is just my personal opinion.

[d_himan]

I had an i10 and Accord AT (TC), have a Baleno CVT and a Polo DSG. Drove my family's Land Rover 6spd AT (TC) extensively. For an enthusiastic drive, as well as fuel efficiency, DSG. Nothing else is close. For the bumper to bumper city commute, CVT/TC are better. TC is horribly FE inefficient, especially in Petrol. (my 5 kmpl Accord and 7 kmpl i10 days..). CVT is better that way, but of course, there's a learning curve to minimise the rubber band effect.

[torquecurve]

I have driven my fair share of Automatics and here is what I feel.
- Nothing comes close to the feel of short throw manual gearbox with well defined gates coupled with an engine with a predictable torque band. Now that we have this out of the way, on with the Automatics

- Torque Convertors - The oldest of the lot, in a way the simplest Automatic out there. Little or no mechanical interference due to the use of Fluid dynamics to act as a coupler instead of a mechanical clutch pack. Supremely reliable if cared for and decently reliable if not cared for. Multiple speed options with similar weight gearboxes and ability to take a lot of abuse/ power increases, etc. Newer generations (still about two decades old), are quick shifting and efficient. Funnily, have heard that the older the oil gets, the slippage improves - improving the traction available.
Pros - Tough, tested, upgradeable, self regulating
Cons - Shift speed (compared to newer DCT/ DSG), efficiency

- CVT - the Sunny Zip (remember this?) had it, the KiHo (Kinetic Honda) popularized it, the Activa bought it to the masses. The Temperamental kid of the automatics. Mechanical belt driven with the ability to have infinite ratios. The infamous rubber band effect - used to good effect in programs like, '…wait for it…' "how I met your mother". The Smoothest of the lot (because of the lack of actual shifts!)
Pros - Unlimited Ratios, efficient, decent reliability (warns you before failing)
Cons - Rubber Band effect, not suited for spirited driving

AMT - Automated Manual Transmissions -
Though, this is new to cars, it has been used for light and medium trucks in the US (Eaton). I had the fortune to drive an AMT equipped transmission, long before it came to India (ok, not too long ago, but still). The high and flat torque band of a truck engine makes the head bob go away. I also own an AMT equipped Nano (low torque), regularly drive a Celerio AGS (medium torque), Recently drove the AMT equipped Nexon (Decently high torque). If driven properly, you can almost predict the way the AMT will shift and your head wont bob (Bob the passenger's head will still nod). The head bob, while not being eliminated completely is almost imperceptible with a high torque engine.
Pros - Reliable (it is an electro-hydraulic system managing a good old mechanical gearbox), cheap to install, can ideally (please read ideally) be implemented on any car
Cons - Head nod, tends to wear out the clutch quicker, not suited for spirited driving

DCT/ DSG
This is my favourite manual automatic transmission. Wait, did I just use 'Manual' and 'Automatic' in the same sentence. Yes, it is because the DCT/DSG is just that, a glorified Manual transmission with a 'electro-mechanical' brain controlling it. Before you kill me, read on please. If you consider the CVT and TC as 'Pure automatics', then the AMT is manual because it has a clutch, then the DSG has 'two' clutches. Additionally, it does actually shift gears like a manual gearbox!. Just like the AMT - it has a mechatronic unit controlling it albeit super quickly. It also allows you to use a 'Flappy paddle' type gear shifter. It is said to be decently reliable (now) compared to the original ones. Is maintenance intensive of course but coupled with a powerful engine it is a superb combination.
Pros - Super Quick shifting, enthusiast friendly (with tip-tronic/ flappy paddle shifting), predictable
Cons - Reliability suffers if not looked after

*** All the standard disclaimers - IMHO, AFAIK and all that

[ShreyasM8]

I guess it all depends on the fact that how effectively manufacturers uses these and how refined are they in the final product.
Choosing one was difficult but voted for CVT for their inherent charecteristics such as the butter smooth function and the peppiness.
But in real world I would only choose if I know which car we are talking about.

[Nav-i-gator]

Originally Posted by torquecurve

DCT/ DSG
This is my favourite manual automatic transmission. Wait, did I just use 'Manual' and 'Automatic' in the same sentence. Yes, it is because the DCT/DSG is just that, a glorified Manual transmission with a 'electro-mechanical' brain controlling it. Before you kill me, read on please. If you consider the CVT and TC as 'Pure automatics', then the AMT is manual because it has a clutch, then the DSG has 'two' clutches. Additionally, it does actually shift gears like a manual gearbox!. Just like the AMT - it has a mechatronic unit controlling it albeit super quickly. It also allows you to use a 'Flappy paddle' type gear shifter. It is said to be decently reliable (now) compared to the original ones. Is maintenance intensive of course but coupled with a powerful engine it is a superb combination.
Pros - Super Quick shifting, enthusiast friendly (with tip-tronic/ flappy paddle shifting), predictable
Cons - Reliability suffers if not looked after

*** All the standard disclaimers - IMHO, AFAIK and all that

Now, this is something I was also thinking about. DCT/DSG has mechanical gears, and clutch (double clutch, but still), and changes gears - Just like an AMT, but does it much quicker. The difference lies in the "brain", the software taking the duty of anticipating the driver inputs and changing gears automatically.

In the same vein, with better software, and with installing two mechanical clutch-gear combinations, AMT can be like DCT/DSG, with super quick responses and close to naught head-bob (and at a much lower cost). AMT is the future.