My take on all the Transmissions:
MT (Manual Transmission):
It is the simplest transmission, with highest reliability with no major maintenance (only oil change). Generally, the gear box will last the life of the car or more. Most widely used transmission across the world (except USA).
Positives:
Mother of all transmissions
Reliable as a rock
Gives complete control to the driver (Can drive it butter smooth or like a maniac)
Highest fuel efficiency (If you change gears at the right time)
Lightest Transmission Hardware
Negatives:
MANUAL CLUTCH (If only left foot was replace-able like a spare part at service centers along with clutch plates)
One part of your brain must keep thinking on which gear to be in
Can stall and switch off the engine if not driven in the right gear
If there is no Hill hold in your car, you have to juggle clutch, gear, hand brake and accelerator all at once.
CVT/X-tronic (Continuously Variable Transmission):
Theoretically the best transmission tech without any compromise. But in real life situations, it is less than ideal. It is THE transmission of all the scooters today and works like a gem.
Positives:
Smoothest of the transmissions
Infinite gear ratios
Best mix of performance, fuel economy (But only in theory. i.e. not true in stop and go traffic situations)
Higher fuel efficiency (compared to other Auto tech, if driven in ideal conditions)
Lighter Transmission Hardware (compared to other Auto tech)
Parking Slot
Impossible to stall
Negatives:
RBE (Rubber Band Effect) - No performance car can have CVT.
Some brands CVTs are prone to have issues
Less suitable for challenging situations like extreme uphill (Slippages can occur)
Suitable for lighter, less torquey cars (Hence mostly available only in Petrol cars)
Most CVTs lack Engine braking
Some CVTs lack Creep function
AMT/AGS/Easy-R (Automated Manual Transmission):
Manual Transmission with an automated shifter. It is like "Chotu 2nd gear lagao". Every shift has to go through engagement of the clutch, change of gear, and release of the clutch. Just like a manual transmission, but robotically operated by a machine.
Positives:
Cheapest Auto tech to buy and repair/maintain
Better fuel economy (Compared to other Auto tech, under all conditions)
Manual Mode available (Just like a MT, but without clutch operation. In some places, it is called Semi-Automatic Transmission)
Performance is as good as MT
Lighter Hardware compared to other Auto tech
Negatives:
Slowest Shifting
Jerkiest of the transmissions (infamous head-nod during shifting)
Less suitable for an upmarket car (lacks a premium feel)
No Parking Slot (Hand brake is the parking slot)
Need special attention and skill if you are rolling down a slope/climbing an incline from stand still
Some AMTs lack Creep Function
TC/Automatic Transmission (Torque Converter):
Slightly more complicated mechanism but have been perfected over the decades. Most preferred of the Auto boxes worldwide. Used in many of the premium brand cars even today.
Positives:
Oldest and most mature Auto tech
Most reliable of the Auto tech
Higher the gears, better the feel and efficiency - (due to wide spread of torque/top end bands)
Smooth in operation (due to the liquid coupling)
Manual Mode (Available in most modern TC Auto boxes, Not very direct, but still better than complete lack of it)
Parking Slot
Impossible to stall
Creep Function
Negatives:
Lesser Fuel efficiency (Though it is improved a lot, transmission losses not completely avoidable)
Heavy Gearbox Hardware
Expensive to repair
DCT/DSG (Dual Clutch Automatic Transmission):
Most desired Auto tech by enthusiasts because of its performance and shifting speeds. It is like an AMT with 2 clutches one each for odd and even gears. AMT's 3 stage operation for shifting is cut down to 2 in DCT - change the gear and release the clutch. It is practically faster than even manual transmission. Used in high-end performance cars.
Positives:
Lightning Shift Speeds
Darling of the enthusiasts, race drivers
Very Direct with no transmission losses (due to the hard coupling)
Higher Fuel efficiency (compared to TC Auto, but only by a small margin)
Higher the gears, better the feel and efficiency - (due to wide spread of torque/top end bands)
Manual Mode
Parking Slot
Impossible to stall
Creep function
Negatives:
Most unreliable of the Auto tech (Highest number of moving parts controlled by electronics)
Even regular maintenance is expensive
Very expensive to repair (Most of these boxes are imported, hence not repairable in India)
Very slightly jerky compared to TC (but no where nearly as jerky as AMT)
Heavier than MTs
Now, coming to which Auto tech to chose:
You must chose the auto box based on your usage. Not due to any other factor.
- If it is driven primarily in city conditions with back-to-back traffic, objective is only to commute, AMT is better. It will not burn a hole in the pocket and if anything breaks down you can fix it cheaper.
- If driven primarily on highways (but with light foot, not trying to race other cars), or in cities with less traffic (smooth sailing with occasional slow traffic), CVT is better (but if you want a big torquey diesel car- CVTs are not available)
- If performance is your thing, the race driver in you is alive, you demand responsiveness and you are done with manual transmission, close your eyes and go with DCT (You can save money on other things, smile on your face will be priceless)
- If you want a mix of all the above - sometimes city, sometimes highway, sometimes traffic, sometimes relaxed driving, sometimes spirited driving, GO FOR TC Auto transmission. It is the best blend, most balanced, it is an all rounder. It is the most reliable auto tech too.
Hope it answers questions on Auto tech selection. There might be some exceptions or outliers, but most commonly these are similar characteristics of each of the auto tech. It will either help you or bother you depending on the situation. So, choose the best tech based on YOUR usage of the car.