[audioholic]

Originally Posted by Sparky

Does anyone know since how long the Maruti is working on this juddering issue? and what is the current status of it?

I doubt if Maruti R&D is actually working on it with top priority! The issues we discuss here are likely to remain unsolved if it does not reach the concerned department of Maruti.

This juddering issue has been worked upon from quite sometime. Hence, an interim software update is released for vehicles manufactured before April 2016. The cars manufactured later already have an upgraded software. However, this is still rolled out on a trial basis and is not yet the concrete solution for the problem. However, in contrast to what some have reported as extremely jerky and improper shifting, this has been resolved. The only pending resolution is for the clutch slipping in second gear, which causes the judder. Once this is out, there will be no more issues

And for those who are claiming that TATA is using a later version of AMT, it is the other way round:

Now, not only is Maruti the first to launch an AMT equipped car, it uses the 4th generation of the Magneti Marelli system, where as industry sources tell us that both Tata and Mahindra intend to use the 3rd generation.

http://overdrive.in/news/maruti-suzu...-transmission/

Hence, I am waiting for that software update. Rest said, the behaviour of the AMT is good and I dont have any issues with delayed shifting or improper shifting. If we get used to modulating the throttle, the shifts happen when we want it to.

[vsathyap]

Originally Posted by Sparky

Can you tell the date when your advisor raised this issue with Maruti? Just trying to know how long the Maruti is working on this issue.

This was probably some time in Oct 2016 when my vehicle went in for the 1st year service. I dont know whether they patched any software/firmware on the TCU/ECU during that time.

Definitely - the AMT has its woes when driven in slow and congested traffic conditions. My car AMT goes through very heavy traffic daily and it takes approximately 1.5 - 2 hours to travel a distance of 15km. A good day means I do the distance in just over an hour. Repeat this distance on the way back home and in even heavier traffic and you've hit the sweet spot for AMTs to judder and eat through clutch plates like it was a vada-pav!

My AMT even had an issue where in it shifted to N automatically in the middle of the road and I had no control over the vehicle. My thread on this issue has been mentioned/tagged by GTO in his comments in the first few posts of this topic.

[sajo]

Originally Posted by vsathyap

Definitely - the AMT has its woes when driven in slow and congested traffic conditions.

When I drove the Celerio AMT (TD car) in heavy traffic, the brake pedal juddered while at a standstill , like a manual car would be if the clutch is held at biting point. Once it got moving, things were fine though. Is this typical of all AMT's or was it an issue with the TD car , the 34k KMs done VXi ?

[vsathyap]

Originally Posted by sajo

When I drove the Celerio AMT (TD car) in heavy traffic, the brake pedal juddered while at a standstill , like a manual car would be if the clutch is held at biting point. Once it got moving, things were fine though. Is this typical of all AMT's or was it an issue with the TD car , the 34k KMs done VXi ?

This is probably the same "juddering" issue we're all discussing here - looks like the TD car also had its clutch plates worn off and the resulting judder explains it.

Yes - once the car moves and is moving in fairly medium traffic, things seem to be fine. Its only at slow speeds when the pathetic low end torque of these "fuel efficient and puny" engines is not sufficient, the AMT makes itself perceivable, a-la-judder.

In medium to light traffic, the gearing ratios are a bit odd in the sense that first gear is very short - second is L-O-N-G and clutch hungry, third gear is almost non-existent and the AMT goes into 4th from 2nd very quickly. The third gear is there just because the AMT is a sequential shifter. It also moves into 5th quite eagerly once the car crosses 45kmph and if we're driving sedately.

The AMT is superb on highways and gives me almost the perfect gear every time I am driving on highways. On overtakes, it slots int the 3rd or 4th gear depending on the road conditions/my speed/load on the car, etc., and sometimes, if one persists (by pressing eagerly on the A pedal), the AMT even shifts into 2nd gear, giving that sweet yet gruff and sore-throaty thrum of the K10's 3 cylinder note. Once the overtaking is done and things settle down, it upshifts into 4th and 5th almost magically and unnoticeably.

The car is really good and steady at 80-90kmph and I felt that taking it beyond 90 or 100 is slightly risky, given the average brakes and noisy and puny tyres. Keeping it at 60-70kmph will yield the maximum FE, close to 26kmpl while the 80-100 band will bring down the FE to 20-22kmpl on pure highway drives.

I personally feel the AMT is happy in medium to light traffic and that's what it's probably meant for. Heavy and stop-and-go traffic makes the AMT eat away clutch plates.

[Numb_Locked]

Originally Posted by audioholic

And for those who are claiming that TATA is using a later version of AMT, it is the other way round:

That's a 3 year old obsolete piece of information from Overdrive.

Mahindra's AMT units are not sourced from Magnetti Marelli, they are Co-developed with Ricardo.

http://www.ricardo.com/en-GB/News--M...-with-Ricardo/

What deeply provokes my curiosity is If Maruti is using the latest version of MM AMT, why are they missing the Sport mode?

[Mafia]

slightly off topic here.

what does the AMT reliability do to the resale value of the car?

would I be brave enough to invest in a used AMT with some 60k on the clock? Not sure.

[mjsraman]

Owning alto k10 AMT for past 1.5 years - done around 15k both highways and chennai t Nagar traffic - no issues to complain - good mileage too - probably it depends on driving style ?

[sachinayak]

Originally Posted by Numb_Locked

That's a 3 year old obsolete piece of information from Overdrive.

+1

The AMT in the Tata Nano is definitely the 4th Generation one.

What's new is the optional 5-speed AMT gearbox (regular Nano has a 4-speed manual). This is a Magneti Marelli-sourced 4th generation AMT unit. It has a manual mode, sport mode and 'creep' functionality.

Source: Team BHP official Review:
http://www.team-bhp.com/forum/offici...al-review.html

[Omkar]

Thanks to Rijesh P R for sharing his thoughts on the Celerio AMT.

Hi Team,

The latest thread on Maruti's AMT woes caught my attention as I own a Maruti Celerio AMT. In fact, I bought my car after reading the official review and risked myself without even waiting for a long-term ownership review because -
1. At that time, I'd almost made my mind to book an A-star automatic
2. It is a Maruti and hence I won't be in a no man's land (I own a Chevy beat as well).

Below are my takes on Celerio AMT.

Likes:

1. The AMT - As the name EZ drive suggests, it is easy to drive.
2. I get all the freedom of AMT and at the same time I can drive in manual mode as well. Also, manual shifts in normal conditions are much quicker.
3. Overtaking is easier when I drive in manual mode as I can shift down and up in a fraction of a second.
4. Fuel Economy - I have achieved the ARAI rated fuel economy on highways. Note that I drive sedately and most of highway drives are done with a maximum speed of 70 km/h and 90% of the drive is with the AC running. My car usage is 50% on highways, 30% in city and 20% on bad patches (village roads) and I got around 18-19 km/l.

Dislikes:

1. As most of them here said - Juddering. I did not care about this issue much until I read about it in one of the ownership reports (Audioholic). I realized that this issue occurred mainly due to my driving habit. In manual mode, I used to drive in 2nd gear when at low speeds or inclines. In D mode, all those speeds would be done in 1st gear. After reading that thread, I made sure on each occasion I downshift to 1st gear at low speeds. I believe that my previous driving habit had already made enough damage to the clutch disc and I need to inspect the same during the next service.
2. While climbing a hill or when you hit pedal to the metal, up shift commands in manual mode are damn slow (2-3 seconds). And by the time AMT shifts, rpm would have dropped down and this results in auto downshift.
3. AMT warning came once when I was on hill roads. It simply showed a blinking light on console (press brake). There was beeping sound and shifts were not working. I turned off engine and waited for 2-3 minutes and turned it back on. Issue was resolved and I have never faced it again.
4. Once, I turned the ignition off when the car was in D mode and then tried to turn on the ignition. Later when I realized that the car is in D, I tried to slot it back to N with brake pedal pressed. It simply refused to move as it used to. Even tried the same without pressing brake pedal and only the brake pedal warning kept blinking. Again, turned it all off, took the key out, waited for a minute and tried again. It worked! Yes, I work in the IT field.

Other observations/points:

1. I was/am totally against Celerio. At the same time, I would only recommend Celerio AMT ZXi(O) for anyone with a specific budget (Not MT).
2. I loved (still love) my beat far more than Celerio. But the Beat has clocked 35,000 Km in last 6 years when the Celerio has clocked 29,000 Km in last 2.25 years. Reason? - AMT.

[Torino]

Though the cure for the judder is still unknown, a quick internet search came up with this AMT driving technique for smooth gear shifts irrespective of the size of the engine and power.

In the 2015 Fiat 500..the automatic manual is not a smooth shifter, and there is a distinct pause as the next gear is selected, particularly with the lower gears and under medium to quick acceleration...you must learn to anticipate the point at which the auto will shift and slightly back off the accelerator, then smoothly reapply it, in exactly the same way you would if it was a manual.link

The Aston Martin V12 Vantage S's automated manual gearbox feels antiquated...remember to lift your foot off the throttle, as you would with a manual box, and upshifts are smooth.link

2014 Lamborghini Aventador uses a single-clutch seven-speed automated manual transmission..it manages to shift a gear in less than 50 milliseconds.link

Well, the Lamborghini may have advanced electronics doing million calculations per second, the other two reviews clearly indicate that you must learn to anticipate the point at which the auto will shift and slightly back off the accelerator, then smoothly reapply it, in exactly the same way you would if it was a manual and the upshifts are smooth. This may not eliminate the judder but probably it can reduce it due to reduced stress on the clutch.

[vsrivatsa]

Originally Posted by sachinayak

+1

The AMT in the Tata Nano is definitely the 4th Generation one.



Source: Team BHP official Review:
http://www.team-bhp.com/forum/offici...al-review.html

Not sure if there is a way to validate what TATA has put inside of the Tiago XZA (AMT) but if they are using the 4th Gen AMT on the Nano, it maybe logical to derive that they would use the same or better in the Tiago as the Tiago is more recently launched as compared to the Nano and is also a segment above as compared to the Nano.

[abhishek46]

It is shocking to see this thread in the first place, because of Suzuki's fair reliability record.

Anyways, some key takeaways, after going through the posts of many users, is that:
1. Smaller Cars with the AMT use their clutch set rather inefficiently.

2. Life of clutches in the above cars looks to be reduced when compared to MT.

3. The problem in point 1 can be solved by tuning both the engine & the transmission shifting logic. However, there will be fuel efficiency penalty. This may have prevented MSIL front doing this.

4. Providing a thicker clutch delays the problem. However, if the thicker clutch lasts as long as a MT clutch, then there should not be any problem in accepting this rather 'cheap' workaround.

5. Hill hold feature is a necessity in all AMT cars. It's not a luxury. This is a basic functionality, which should have been provided in first place.

6. Under hard acceleration, the AMT shifts are pathetic. Can someone pls explain the technical reason behind it? What causes the AMT to be worse than a manual transmission in such scenarios?

7. To avoid the issues in inclines, can sensors inside the car sense the gradient of the road and alter the clutch slip on fly based on the gradient of the road, speed of the vehicle, present gear, rpm, load etc?

Originally Posted by Torino

you must learn to anticipate the point at which the auto will shift and slightly back off the accelerator, then smoothly reapply it, in exactly the same way you would if it was a manual and the upshifts are smooth.
This may not eliminate the judder but probably it can reduce it due to reduced stress on the clutch.

That defeats the whole point of an automatic.

[flying_spur]

Originally Posted by Torino

you must learn to anticipate the point at which the auto will shift and slightly back off the accelerator, then smoothly reapply it, in exactly the same way you would if it was a manual and the upshifts are smooth.

On a lighter note, we can get the so-called "feel" which we generally miss while driving an automatic , as well as leave the left leg happy

[audioholic]

A few pointers:

Originally Posted by abhishek46

2. Life of clutches in the above cars looks to be reduced when compared to MT.

Not exactly. Judder is not due to a worn out clutch. It is due to warpage of the clutch disc which is caused due to slipping the clutch. The clutch disc was looking as good as new in my Celerio when it was replaced. However, there would be minute variation in the thickness of the friction material.

3. The problem in point 1 can be solved by tuning both the engine & the transmission shifting logic. However, there will be fuel efficiency penalty. This may have prevented MSIL front doing this.

There wont be a fuel efficiency penalty. If they really fix the software, it will lead to an acceleration lag in second gear due to the rather weak low end of the K10. To avpid this, the morons who programmed the AMT replicated how we try to launch off a hump in half clutch and second gear and programmed the AMT to slip the clutch at low speeds in second gear. This both screws up the clutch disc and causes the judder. It is present even in MT cars in which the drivers have a habit to ride the clutch. If this is reprogrammed not to slip, it will cause a slight delay in the acceleration but will solve the problem. To compensate, the shift point of 1-2 can be moved up a bit.

If they realise this, the fix is SUPER SIMPLE. However, they have not done so. I am hoping that this will happen soon.

6. Under hard acceleration, the AMT shifts are pathetic. Can someone pls explain the technical reason behind it? What causes the AMT to be worse than a manual transmission in such scenarios?

In my experience, it is the other way round. Under hard acceleration I love the AMT for very accurate shifts. It holds gears upto 4k RPM or even more and only then initiates an upshift. Once the throttle is eased, it settles down in a comfortable gear. Even shift speed is quicker under hard acceleration except for 1-2 since it takes a longer time to rev match due to the improper ratios.

During light acceleration, the AMT is annoying. It advances gears quickly, and a slight press of the pedal will trigger a downshift. Imagine how horrible it feels to find the car in 4th gear at 40kmph. However, in my car, it is history. I have given enough training to the AMT that it doesnt shift to 4th gear before 55kmph and 5th comes in at 70kmph.

A temporary fix that I found out for the judder issue is to force the AMT to shift to 1 when below 20kmph. This can be done by a momentary kickdown of the accelerator pedal. Did that a few times and now the AMT learnt that and shifts to 1 if I slow down for a hump and doesnt judder while accelerating

Originally Posted by abhishek46

7. To avoid the issues in inclines, can sensors inside the car sense the gradient of the road and alter the clutch slip on fly based on the gradient of the road, speed of the vehicle, present gear, rpm, load etc?

Forget altering the slip, I wouldnt want any slipping at all. The powertrain is powerful enough to handle inclines without clutch slipping. The selection of gears is accurate and also takes into account the inclination. It is just a comfort function to slip the clutch and give a 'feeling' of being smooth whereas it is the opposite way.

[a4anurag]

Originally Posted by audioholic

A temporary fix that I found out for the judder issue is to force the AMT to shift to 1 when below 20kmph.

I do the same when I took it out but I am 96% of the time on 'M' mode (I know, it beats the purpose of AMT), so the moment I need to slow down below 15 kmph, I downshift to 1st. The drive thereon is peaceful.

I have asked my wife to do the same as you do to kick down. Let's see how things go about.