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-   -   Maruti Alto: AMT makes the car suddenly "jump" ahead (https://www.team-bhp.com/forum/technical-stuff/192414-maruti-alto-amt-makes-car-suddenly-jump-ahead.html)

20000km Update: (This is becoming a part ownership review of sorts!):

My Alto K10 AMT odo now stands at approx 19450km and its been 2 years of ownership - as you can see, we've driven the car close to 10K km per year which is decent. The AMT juddering problem has reappeared with the replaced clutch as well. Its been close to 10000km since the clutch was last replaced and like clockwork , the juddering is back - and this time with a BANG! Details below...

When the car is in 1st gear in D or M mode, and I release the brake pedal to start the creep function, the car moves ahead with a massive jerk. The entire engine compartment judders and shakes like its gonna fall off its mounts and the car makes this frightening "ghad ghad ghad ghaddddd" sound. You can relate this to a person learning to drive a Manual Transmission car - trying to get a hang of the clutch in first gear. That inexperienced left foot lifting up too quickly, yet holding on to the clutch causes a jerky "jump" that we have all experienced in our learning days - the AMT is doing exactly this when the car moves from a standstill and is trying to creep. It lunges forward wildly!

Worse still, once this jerk is done, the AMT feels like it has engaged "half" clutch and is still slipping the clutch to move forward and when I try and brake (instinctive reaction to the "Jumping Start" and the lunge).... the brakes feel spongy and don't bite in initially and after the clutch slipping is complete, the brakes find their bite and BAM! I've stopped the car like some emergency braking maneuver.

Its hard to explain this in words but its like holding a running person's shirt and you get pulled with him - you feel the pull initially and get pulled with him, but you are still slowing him down - just not enough to make him stop. Then suddenly you get a better grip and pull him harder and he stops dead in his tracks like he hit a wall or something.

In stop and go traffic, this entire jump-creep-brake=> jump-creep-brake=> jump creep brake cycle takes a toll on my nerves and it gets very very frustrating to drive, quite the opposite feeling when one is supposed to have while driving an Automatic.

I took the car to the scheduled 24month/20000km service in the last week of October and complained of the same juddering and jumping issue. The SA, as expected, didn't do anything about it and murmured something like "yeah its common but we've taken a look at it". After the service, the AMT Jump became more and more aggressive and at one point, I almost hit a bike in front of me when the car pounced like a cheetah - in the 1D gear after a traffic signal turned green. I was trying to brake but the AMT and the TCU had a mind of their own and kept lunging forward. Thankfully, the brake bit and I came to a sudden halt, only to be honked by the impatient people behind me. Again, thankfully, no one rear-ended me.

Another issue is that the reverse gear feels like its on steroids, or is powered by rocket fuel. Engage the reverse gear and allow the car to creep slowly is what one should (and would) expect but surprise surprise - it moves like a rocket! Reversing is so fast that if one is not aware that the car zips back so quickly, they can really hit something/someone and cause serious damage.

So, I went back to the service station with this problem and the SA had another person (probably a senior floor mechanic) take the car for a spin. I was sitting in the passenger seat and was explaining the phenomenon to him. During his drive, he experienced the AMT JUMP too and was quite rattled by how the car lunged forward at a U-Turn, while he almost hit vehicles coming in the other lane, into which he was merging. He agreed that the Jumping in the first gear is a problem and he also noticed the 2nd gear judder.

We came back to the service station after our test drive and he spoke to the SA who had worked on my car. They went in for some discussion and later, my SA came and told me that he will be reporting this to Maruti and they would wait for more technical assistance from Maruti Suzuki themselves. This is because the Clutch has already been replaced once and the second time replacement would raise questions and hence, they wanted to involve Maruti Suzuki.

So, I was told to wait on the issue and that I will be contacted by the SA when Maruti Suzuki gives them a go ahead for another clutch assy replacement, or calls in the vehicle for further inspection.

So that's what I am doing right now - just waiting for the SA to contact me (its been close to one week now) and hope that some solution is offered to this mess called AMT.

This has been so frustrating that my fellow passengers ask me why I'm driving like a cabbie (no offense to cab drivers) with constant stop-go-stop-go-stop-go kind of aggressive driving. I try to explain to them that its not me but somehow, they don't seem to understand the full story.

I have a feeling that Suzuki is persisting with the AMT only because it's cheap. But they must keep improving and refining the AMT: they're India's largest car maker they can't afford to be complacent. I'm sure a few years down the line if the AMT becomes very unreliable they will be forced to recall.

This may be OT but here is my 2 paisa worth:

I drive a Alto K10 (manual transmission, my wife's) every now and then and I find it very difficult to drive in 2nd gear. In that gear, the torque seems very low and you have to compensate by revving the engine and slipping the clutch a bit. I think those of you who are driving a lot in the 2nd gear zone are burning your clutch.

I would think that if the AMT is programmed to avoid the second gear as far as possible, it might solve this problem. And that is what I do on the MT - stick to 1st gear, when going slow and shift up to 2nd gear at a much higher RPM. This will increase fuel consumption and that is why Maruti is happy to replace clutches for the few affected by this problem. The vast majority are happier with the higher fuel economy.

I have an A-Star automatic, with essentially the same engine, but the torque converter makes the car seem very powerful and smooth.

Hi Vsathyap, this problem surely deserves its own thread, hence moving it into a new discussion. Thanks for sharing!

The original thread is here.

Clearly a lot of fine-tuning & tweaking is required on the new AMT tech. What you're experiencing has serious safety concerns. Would suggest that you also write to Maruti with a link to this thread.

Only maruti can help with this since AMT's rely on software and hardware to work seamlessly and sure seems to be an issue with this unit. Judder one can understand but the leap in forward and aggressive acceleration in reverse are really out of the ordinary wear and tear. Hope MSIL take a hard look and replace the unit under warranty.

The 3-cylinder k10b engine already suffers from poor low-end torque, alongside a light but a snappy clutch(which needs to be adjusted frequently). I am not an expert but to me it looks more like a clutch release bearing/bad clutch adjustment issue rather than the software. If neither is the problem the entire AMT unit has to be replaced to see if the issue is resolved.

Thank you for your inputs GTO. Yes, its quite unnerving to drive the car in tight traffic, specially after driving in heavy traffic for 30-45 minutes. The juddering and jumping become more and more aggressive as it gets heated up.

Could you please PM me/ direct me to the contact details of Maruti so that I can write them an email about this issue as you mentioned?

@ vsathyap, this is extremely nerve racking to even read, I can only imagine how scary it must be behind the wheel. Having unpredictable responses from a car on our already unpredictable roads is a dangerous situation. If at all possible, do try to avoid driving the car until this issue is fixed, because from the way you describe things, it is only a matter of time you will unintentionally scrape/rear end something and add to the stress of this whole thing.

I hope that Maruti solves this issue as soon as possible, otherwise it will create negative ripples regarding AMT. The same issues mentioned in the previous thread went unnoticed by Maruti, I think. I request members who have access to concerned Maruti personnel, please make them aware of this. When I faced the juddering problem, I tried to reach Maruti on their website, but was reverted back with local SA and was offered clutch replacement. Now I cannot complain back unless juddering issues crops back.

I would like to mention that after driving in heavy traffic for long time (about an hour), I can slightly feel juddering. My normal usage is such that I hardly have to drive that long in heavy traffic, so do not experience juddering under normal conditions.

@vsathyap, please keep us posted of any solution you get, and keep following with SA and Maruti.

This is quite unnerving. I have a Celerio AMT as well (2800 Km done) and was facing this massive jerk issue, although in my case it used to happen while the AMT was downshifting from 2nd to 1st.

I specifically mentioned this to my SA during 2nd service. He and a 'senior' took my car for test drive without telling me (I was waiting in the lounge) and came back and said they didnt find any problem. After reading your post I feel I should have gone along on the test drive.

Anyway, after I took the delivery of the car, this issue disappeared, although its only been little over a month since then.

Currently, quite often there is a judder from 1st to 2nd gear and sometimes its too strong as if someone held me by my shoulders and proceeded to rock me back and forth.

Im worried how long will the clutch last (I guess its already taken a beating) and will they pin it on me.

I sure hope Maruti takes note of this thread and does something abt it before they end up with massive recalls.

Does your car have a tachometer (I believe it does stupid: )? Does the rpm fall when the "jerky jump" happens, or is there a surge in revs?

One thing that needs to be recognized for an AMT is that it is not a true 'Automatic transmission', the entire gear and clutch assembly is still there, just that the onus of pressing the clutch and shifting the stick has moved to the engine/ECU.

Think of driving a manual Alto, put in first gear and then release clutch without pressing the accelerator, then at the point of stalling press the clutch again. It will kill the clutch and make for a terrible drive.

The 'Creep' that most companies are selling now, is nothing but the engine torque responding to a released clutch. In Alto's case given the smaller engine, the creep is translating into almost stalling only the auto box won't allow stalling. You wouldn't see this in say an XUV5OO.

Suggestion: Try to press the accelerator a little bit when starting from a dead stop, if the traffic demands immediate deceleration, slip the auto box into N.
In subsequent gears the problem will not arise as the accelerator would be pressed already.

I own an Alto K10 AMT which was bought in Feb 2017. I have crossed 13,000 kms in it. I am still facing the judder issue from 1st to 2nd and its occasional. However I am facing really low pickup while using a/c and also gear shifts happen early. For example, the AMT shifts to 4th gear before i hit 40km/hr. Will try to check it this weekend.

@Varunsangal - I agree with your suggestion. We need to press the accelerator a bit more when we move from N to 1 or 1 to 2.

vsathyap, you have explained the experience really well. I could really picture it and that is scary!!

It's no secret that AMT is best suited for bigger engines which has more torque in the lower RPM. So, the best integration of the AMT I have driven is the 1.3 MJD.

Maybe the K10B with its very poor low end torque isn't really suitable for AMT and ideally needs a torque converter where the transmission supplements the torque output at lower RPM. But then, MSIL ditched that for cost efficiency and F.E. And the market lapped it up.

Also, I think MSIL has tuned Alto AMT very conservatively compared to the Celerio AMT where the drive-train behaves in a much better way on road.

Maybe all of that is not helping the cause of Alto AMT in the long run. Hopefully MSIL will take this up very seriously and come up a fix without delay.

I had this problem with the first clutch kit. It started juddering so much within 3k kms that when parking it required good control on the brakes to prevent excessive movements due to the jerk. However, it disappeared with the second clutch kit and I did not face that much of a judder with the second kit. But I must say that this is very annoying and also dangerous.

While the second clutch developed minor judder in 4k kms which was again replaced, the third set is surprisingly running smooth after covering 8k kms on it. No judder and the jerking is very very rare, upon repeated acceleration and braking which lasts for a second. Hence I am curious to know if they have modified the clutch kit or the software. IIRC, they had released a new AMT software which took care of most of the problems in the cars from June 2016. Hence if your car is older than that it needs a new software and a new clutch kit and not just a new clutch disc.

The main flaw I see in this implementation of the AMT is the setup for clutch control. In the K10, the clutch is mechanical, and the AMT hydraulics controls the movement of the clutch fork which in turn controls the clutch release bearing. Hence, the AMT has no direct control over the clutch release bearing, due to the action of the clutch fork. This is why at the bite point, it faces difficulty in maintaining the clutch at a consistent position. When it tries to modulate the pressure, it results in these jerks.

In contrast to the implementation on the 1.3MJD, the clutch control is hydraulic in the manual version. This is directly automated by the AMT and there is no intermediate setup. Hence, the AMT unit can have better control on the clutch engagement and disengagement by being able to vary the pressure on the clutch slave cylinder directly. This is what results in smoother control and no complaints of judder or jerks heard till now by the users of the diesel AMTs and even the Dzire petrol has a hydraulic clutch I suppose.