[lloydofcochin]

Interesting discussion on AMTs. So let me share my experiences with AMT Cars that I've driven.

1) My friend bought a Tata Zest Diesel AMT in Nov, 2014. The Car has currently crossed 85k and it has absolutely no issues with the AMT. In fact the other day he was saying how good a buy this was since he drives a lot for business and the AMT is a boon for him. Of the 85k that the Car has done I would have driven around 10-11k during our trips together and I've found the AMT to be very smooth. To make the driving experience seamless I give the Acc input like we drive a manual. I'll accelerate enough for it to shift and then as it is shifting I ease off and once the upshift is done I'll accelerate and get up to speed. I've felt no juddering and he hasn't complained either. No clutch replacement required either (Maybe due to 80%+ usage on Highways)

2) Another of my close friend has a Wagon R AMT. He is a first time Car buyer and his Car has now crossed 10k kms. I've driven his Car for 700+ kms and I found the AMT to work flawlessly. The shifts are a bit slower than the Zest and isn't as smooth either but no reasons to complain.

3) Another friend has a Nano AMT. I've driven it couple of times in the City and its an excellent Car. Shifts are pretty smooth and I would put it just below the Zest in terms of my favorite AMT. My friend is extremely happy with his choice and his other Car is a Manza.

So I feel that Tata has probably tuned their AMT's better / they might be using a more superior AMT kit from Magnetti Marelli.

[vsathyap]

Originally Posted by lloydofcochin

Interesting discussion on AMTs. So let me share my experiences with AMT Cars that I've driven.

1) My friend bought a Tata Zest Diesel AMT in AMT to work flawlessly.

Two very valid points that could favour the Zest:

1) Could it be that the low end of the diesel mill offers better torque and the AMT will use this strong bottom end torque to pull forward rather than slip the clutch and hence reduce or eliminate the issues of juddering?

2) More importantly the Zest is a higher powered engine compared to the K10, which has enough power on tap but it's lousy low end causes the driver (or the AMT) to rely on slipping the clutch for a smoother drive in second gear.

What's a common trend in all these discussions is that the AMT used in Maruti vehicles all show issues in lower gears like 1, 2 and R while they are fine in higher gears. This clearly points to the K10s abysmal low end torque.

I miss my MH410 Zen in this regard.

[thehighwayman]

Is there a specific reason why Maruti opted for a relatively unproven technology like the AMT when there are tried and tested technologies available like the CVT?

[qr20de]

Originally Posted by thehighwayman

Is there a specific reason why Maruti opted for a relatively unproven technology like the AMT when there are tried and tested technologies available like the CVT?

AMT is a relatively new word that has coined (not sure by whom) to market the technology. But the actual technology is quite old and very much proven, even in racing. For example, Alfa Romeo introduce this tech in 1999, which was developed by Magnetti. I believe GM developed it in the 1960s.

This tech is essentially a sequential manual transmission controlled by a computer. In development/troubleshooting terms there is actually much more that could go wrong with a CVT than with an 'robotic' transmission.

[archat68]

Originally Posted by thehighwayman

Is there a specific reason why Maruti opted for a relatively unproven technology like the AMT when there are tried and tested technologies available like the CVT?

Because it's cheaper, more fuel efficient and less complicated to maintain.

[spd_tkt]

I have had my doubts about AMT gearboxes and this is a topic I always wanted to discuss about even though I do not own a car equipped with AMT. I have some experience with Alfa Romeo cars in the past having owned and worked with some of them http://www.team-bhp.com/forum/long-t...-workshop.html and from my understanding, Alfa Romeo was one of the first brands to come up with Selespeed transmission, and if have not mistaken, it is a bit too similar to the present AMT transmission seen on Maruti, Tata and other cars especially considering the price point of these cars and Magnetti Marelli being the supplier.

Now you only have to google 'Selespeed' to see the horror stories associated with this transmission. Italian electrical jokes aside, I have had the misfortune of experiencing selespeed failure on some customer cars and that awkward situation when you are at a signal and the car refuses to engage any gear! I understand that earlier BMW SMG and some other manufacturers use similar technology but I think the hardware is much robust or the implementation of the technology is different.

While running the garage for Alfas we made most money from Selespeed failures and we always advised our customers to opt for models without it. In fact my two Alfas were manual, Alfa also had something Qtronic/ Q system which had a torque converter equipped transmission and it was far more reliable. Back to the selespeed, the idea itself is simple with some robotic arms moving the manual gearbox but the many sensors that can fail intermittently, the primary pump that may not get up to pressure warranting a pump replacement, the actuators that fail and the clutch calibration that needs constant adjustment for everything to work properly. It was just too many variables to go wrong and the failure often results in not just judder or loss of power but a complete inability to shift gears. We even wired a toggle switch from the battery for one such car to act as a hard reset because he experience transmission failure so many time.

For someone familiar with UAE, I can cite examples of being stranded n Sharjah - Dubai traffic in Ramadan or getting a call at 2:00 am from a customer whose car refused to engage gear in Ajman while I lived in Dubai! I had FiatECU scan equipped on my laptop to diagnose selespeed faults and it was of some help in trying to identify what went wrong. I alsohave the diagrams and circuits for these transmission and I am sure some of the more technical persons on this forum could identify if the AMT and selespeed are similar systems.

[vsrivatsa]

In the meanwhile, TATA Motors has gone ahead and launched Buses with AMT:
Tata Motors launches AMT buses

"Having developed the AMT technology for our buses with WABCO, we will continue to work with partners like them to develop and introduce products with best-in-class value proposition, delivering world-class solutions for the Indian customer"

WABCO: URL

[outdoorlover]

Originally Posted by thehighwayman

Is there a specific reason why Maruti opted for a relatively unproven technology like the AMT when there are tried and tested technologies available like the CVT?

The straight answer is cost! The main problem in the widespread adoption of automatics in India was the prohibitive cost of the AT (both torque converter and CVT). AMTs being considerably cheaper, found a ready market in low end Maruti models and TATA cars. Higher end models of the same manufacturers donot use AMTs.

[cityslicker86]

Originally Posted by a4anurag

I am drafting an email to be sent to Maruti with this thread link so it does occur in their heads to get down to perform the RCA (Root Cause Analysis) and get us solutions.

Could you mail them? It will be great to see Maruti's response to it. I hope this thread gets them in a huddle about solving AMT issues at the earliest before it creates negative image in the market and drives away customers.

Also, I read somewhere on this thread that Maruti's AMTs come with 10 year warranty. Is this true?

[Sankar]

Originally Posted by spd_tkt

...the primary pump that may not get up to pressure warranting a pump replacement, the actuators that fail and the clutch calibration that needs constant adjustment for everything to work properly.

Why not let the engine drive a more robust primary pump in all these single clutch robotised transmissions? That should be far more reliable right? Probably production constraints and complexity as it wont be a compact independent unit anymore.

Originally Posted by spd_tkt

I alsohave the diagrams and circuits for these transmission and I am sure some of the more technical persons on this forum could identify if the AMT and selespeed are similar systems.

Oh yes both are similar. Different generations probably.

[audioholic]

Originally Posted by Sankar

Why not let the engine drive a more robust primary pump in all these single clutch robotised transmissions? That should be far more reliable right? Probably production constraints and complexity as it wont be a compact independent unit anymore.

Oh yes both are similar. Different generations probably.

If its an engine driven pump, the transmission wont be able to operate when the engine is not running. Even if there is some sort of accumulation mechanism, it will lead to storing pressurised fluid for prolonged periods of time, especially when the car is not used for a longer time.

However, the current system is electronic. In Magnetti Marelli AMT, the pump pressurizes the system when we open the driver door/passenger door if the vehicle is in off condition, or when required. It doesnt run continuously and runs for a brief period of 5s or less if there is already some residual pressure. Also, rather than the longevity of the shifter, I am more concerned about the clutch actuator. But these days, electronic solenoids and control systems are far reliable compared to before. The same type of mechatronics are used in ESP/ABS which is again a safety critical component. The solenoids are usually designed for a huge number of operation cycles.

In the Kwid, the pump runs once the ignition is turned to ON position. Hence, there is a delay required before one can crank the car. This is the difference in implementation from supplier to supplier. And compared to the MM unit, this does not change behaviour depending upon driving style. Neither does it have the capability to learn the clutch position and creep. I think such a system will be more tricky once the clutch wears out. These products being relatively newer compared to the MM AMT, we are still not seeing much of issues.

[spd_tkt]

In the Alfa, the pump would prime itself when the door was opened if I remember correctly. This would give adequate time to build pressure rather than actuating the pump from the key on position.

[Torino]

Originally Posted by cityslicker86

Also, I read somewhere on this thread that Maruti's AMTs come with 10 year warranty. Is this true?

Yes, it's true. Maruti Suzuki offers 10 year or 1,60,000 kms warranty on the AMT unit. link, link.

[bhp_maniac]

My wife got a Celerio ZXi(O) around Jan of this year. The decision was made after TD'ing a relative's Alto AMT which has done around 15k on ODO and was touchwood. I am driving the Celerio for ~120km daily for the past few days. So, here's my two cents on the topic.

1) Shifts are predictable and consistent most of the time, haven't experienced any judder. PS: I have never accelerated it hard from a stand still, always use a light foot.

2) AMT box gets confused on slight inclines, especially with early upshifts. This is really evident when we want to slow down on an incline (e.g. when a slow truck is in front). I mostly shift to "M" in such situations.

3) Most of the time, I use "lift the foot to upshift", this works like a charm

4) FE is around 19.5 with 50-50 highway to city drive and A/C ON most of the time


One has to consider the fact that it's a manual gearbox underneath. It's just that some hydraulics are taking care of shifting the gears. All issues like clutch judder and a worn out clutch disc can happen in an AMT as well. There's no point in expecting it to behave like a conventional AT!

To conclude,

Do I like the AMT experience? Definitely YES, since it gives a stress-free driving experience in the daily commute without sacrificing on the FE department.

Will I consider another AMT? Yes, for sure. In fact, am seriously considering Duster AMT as a replacement to my aging Swift.

[jaaz]

Planning to buy a Diesel AMT. Either Ignis or the New Dzire. There are very few Diesel AMT owners on the forum. In fact, suggestion given on official review of Ignis, is to prefer Petrol AMT over Diesel.

Would be keenly following up the thread.