[Aurum]

Originally Posted by Santoshbhat

I think the key to keep the DSG from breaking down is to prevent it from getting overheated. Shifting to neutral at signals and shifting to manual mode (1st gear) in crawling traffic : are two practices that have become second nature.

Originally Posted by JoshMachine

Very true. Thanks for pointing out again!
In fact these are perhaps one of the most important things to remember by us drivers.
Relieving the heat and stress off the clutches when not required, will not only lengthen their life span but also help in other associated components like the hydraulic pump etc to "relax".

Great thread!

I used to do this with the Jetta (i.e. shifting to neutral). However, I have been reading up on many forums (e.g. this one https://www.briskoda.net/forums/topi...ld-or-neutral/) where some folks authoritatively claim that wet-clutch DSGs do not really need this behaviour. As long as the brakes are applied (physically or via auto-hold), the system is not really "under strain". I am liberally relying on the Audi's auto-hold feature these days in Mumbai traffic.

[Traveler]

Just wow. Thanks for contributing such immense knowledge and insight on the DSG. I can only imagine the time and effort it must have taken you to compile this.

I do have a small question. What is the state of the clutch in a Polo GT Tsi that is idling on a red light with the gear selector in Neutral and brake pedal pressed. Is the clutch engaged or disengaged. My question comes from the point made earlier in this thread that moving to a neutral position is a good practice. I do however feel that if you are in neutral but the brake pedal is pressed then the clutch may still be in action waiting for the gear selector to be moved into the D or R position. To truly disengage the clutch one should be in N position with foot off the brake pedal and or the handbrake engaged.

Please shed some light on this.

[Joxster]

Originally Posted by AMG Power

The RS 245 comes with the DQ 381.

Thank you very much for clarifying mate!

Originally Posted by JoshMachine

Thanks Joxster!And congrats for your Octavia DSG vRS245 booking. Man, that is going to be one damn hot car to drive! And the "black magic" color (IIRC that's the color you have selected?), is going to make your car invisible when you drive on those European motorways!
I travel occasionally to Mechelen and to Europe in general also for work and will keep a watch when I visit next month!

Thank you very much for both the compliment, and for your suggestions as well mate! You got the color right
If you travel often to Mechelen, Belgium, then please feel free to PM me the next time you're coming here, and let's see if we can meet up

Cheers

[Guite]

This is a very informative thread. Saving for further future reading. On my IPad the technical images are slightly blurry. Sharper images would have helped a lot.

Overall the technology is very complicated, a far cry from the fully mechanical Ambassador days. It is from this thread that I have begun to understand what the oft repeated “megatronic” unit is. It also makes me wonder how come VW has not been able resolve the issues pertaining to it, after so many years of data and refinement/development.

[Sutripta]

Originally Posted by Santoshbhat

I think the key to keep the DSG from breaking down is to prevent it from getting overheated.

Always wondered why the control unit does not take preventive/ corrective action (and warn the driver) before more permanent damage occurs.

Regards
Sutripta

[Traveler]

Originally Posted by Sutripta

Always wondered why the control unit does not take preventive/ corrective action (and warn the driver) before more permanent damage occurs.

Regards
Sutripta

The Polo GT Tsi manual has a section on this. There is a warning light indicating high temperature that turns on to warn the driver of such a situation. The recommended solution is to either stop and park the car or drive above 40kms per hour I think. It states that this can happen is stop an go situations.

[Sutripta]

Originally Posted by Traveler

The Polo GT Tsi manual has a section on this. There is a warning light indicating high temperature that turns on to warn the driver of such a situation.

High temp of what - engine or DSG? Or combined.

Regards
Sutripta

[Traveler]

It clearly specifies in the manual that if the Gearbox oveheats it will show up on the dashboard. So it means that it is for DSG only. Engine temperature is anyway being displayed all the time. The procedure to mitigate the gearbox overheating also points to the same logic that the warning is for DSG only.

Here is the page from the Polo GT TSI Manual explaining the DSG Overheating situation and how to mitigate the situation.

[Sutripta]

^^^
Begs the question - If it can protect itself, why the (large number of cases of) permanent damage?

Regards
Sutripta

[R2D2]

Originally Posted by Sutripta

Begs the question - If it can protect itself, why the (large number of cases of) permanent damage?

It's mainly the electronic components and/or actuators in the mechatronics panel that fail. I am not sure to what extent these mechatronics components are affected by high temperatures and if they can do a self-diagnosis for component fault detection at regular intervals. These failures are mostly in tropical and subtropical climates while DSGs go experience fewer failures in temperate and northern climes. In fact being stuffed with more and more electronics has been the bane of EU/German cars, they rarely face mechanical failures.

Any resident DSG expert - please correct me if I am wrong.

[Kosfactor]

The 'Overheating in the DSG' section talks about stopping the vehicle (crawling traffic) and let it cool down , this can happen to inexperienced drivers of manual transmission as well, unfortunately no light is there to warn them of the obvious clutch burning smell.

The scenario however is very real for us folks who travel from far away places to notorious Bangalore tech parks everyday.

While traveling to office in the airport volvo bus for many years in Bangalore which is notorious for traffic snarls, the bus driver only needs to use the brakes to inch forward in traffic for hours . Certainly, the transmission fluid is getting heated and has systems to keep that cool as well, which is why I think a torque converter system will have better chance in Bangalore city traffic. No doubt it's easier to drain a fluid and refill rather than replacing clutch plates.

[JoshMachine]

Originally Posted by Paleo

Is there a version of the software, that I can ask for - that would help me with gear shifts suited for sedate driving? Or that's not a possibility?

I would doubt if there was any such specific software version available. However, to stay relevant on this topic, there is a process called "adaptation" which essentially alters or resets the basic gear shift settings on a mechatronics unit. Here, the engineers try out a series of pre-programmed settings for creep, rpm calibration etc with a road test in various conditions, that beds in the gearbox to real-world conditions. Most of the cases, this adaption is carried out on new or replaced units.
You may want to have a word with your service advisor and ask him/her to re-check or carry out an adaptation for you. However, I doubt if they would oblige unless there is a genuine issue with the gearbox.

Originally Posted by Aurum

Great thread!

I used to do this with the Jetta (i.e. shifting to neutral). However, I have been reading up on many forums (e.g. this one https://www.briskoda.net/forums/topi...ld-or-neutral/) where some folks authoritatively claim that wet-clutch DSGs do not really need this behaviour. As long as the brakes are applied (physically or via auto-hold), the system is not really "under strain". I am liberally relying on the Audi's auto-hold feature these days in Mumbai traffic.

I think there are 2 different things possibly being referenced here -
one, about the wet clutched gearbox's ability to tolerate more of the "holding". This is because this gearbox has an oil circuit which is specifically devoted to cooling the multiple clutch plates and hence that helps in protecting the plates in terms of not directly causing them to wear and tear. However, even this has a specific tolerance (although much higher than the supposedly "dry-clutched" gearbox).

The second point is about the braking part or the auto-hold function. To the best of my understanding, the car's auto-hold feature is a virtual extension of the electronic parking brake system and has not nothing to do with the gearbox as such. This auto-hold is supposedly powered by the car's ABS/ESP unit. With auto-hold function /button ON, the brakes will stay applied when you brake your car to a complete/gradual stop, say at a traffic signal or in slow-moving traffic. If you put pressure on the accelerator pedal, the auto-hold eases and the car will start rolling again. So, in a way, it is independent of the gearbox function.

Originally Posted by Traveler

Just wow. Thanks for contributing such immense knowledge and insight on the DSG. I can only imagine the time and effort it must have taken you to compile this.

Thanks, it did take me over a month to put together all the stuff and then another to organize all the info into a legible sequence

What is the state of the clutch in a Polo GT Tsi that is idling on a red light with the gear selector in Neutral and brake pedal pressed. Is the clutch engaged or disengaged.
Please shed some light on this.

If the gear selector lever is in "neutral" and the brake pedal pressed, then the clutch is fully disengaged. However, the gear selector is held in this position via a definite oil pressure.

Originally Posted by Guite

This is a very informative thread. Saving for further future reading. On my IPad the technical images are slightly blurry. Sharper images would have helped a lot.

Thanks Guite!
The technical images have been extracted from the technical manuals. I did try to enhance them in every way possible but couldn't do beyond a point. If you are interested, I have provided a link in the "References" section, maybe you can download the manuals from there.

It is from this thread that I have begun to understand what the oft repeated “megatronic” unit is.

It is actually spelled "mechatronics"

It also makes me wonder how come VW has not been able resolve the issues pertaining to it, after so many years of data and refinement/development.

In fact, VW claims that no major issues (i.e. for the 7-speed dry clutch gearbox DQ200) have been reported since the last few years. However, it must be mentioned that, VW didn't probably anticipate the change in climatic conditions to have such a severe impact on the underlying technology.

[Traveler]

Originally Posted by JoshMachine

If the gear selector lever is in "neutral" and the brake pedal pressed, then the clutch is fully disengaged. However, the gear selector is held in this position via a definite oil pressure.

Clutch dis-engaged translates to pressing down the clutch pedal in a manual shift. When you leave the clutch pedal it gets engaged and transfers power from flywheel to the transmission. Am I correct in my understanding?


So if the above it true then the correct way to completely rest the DSG clutches would be to stop the vehicle, put it in neutral, apply the hand brake and then remove one's foot from the brake pedal.



The moment you press the brake pedal the clutch gets dis-engaged waiting for you to slot into "D".

[JoshMachine]

Originally Posted by Sutripta

Always wondered why the control unit does not take preventive/ corrective action (and warn the driver) before more permanent damage occurs.

There are mainly 2 types of preventive/corrective actions taken or provided:-

• To address overheating of the gearbox

• To address any other fault which requires detailed inspection

The first point has been already explained by BHPian Traveler, with an excerpt from the owner's manual showing the warning lamp which flashes on the MID. This is also accompanied by an acoustic tone. This type of problem can be supposedly addressed by the driver - either by parking the car (incase its a one-time warning) or switching off the car (for repeated warnings) and allowing the gearbox to cool down.
For the second point related to other/non-heating/potential serious faults, a flashing "spanner" warning lamp appears on the MID alternated by the current position of the selector lever.

VW says in the manual that "failure to observe illuminated warning lamps and tones can lead to your vehicle breaking down, can cause accident and serious injury".

Originally Posted by Traveler

Here is the page from the Polo GT TSI Manual explaining the DSG Overheating situation and how to mitigate the situation.

Thanks for sharing, Traveler. There is also a section in the manual that shows different types of warning lamps and possible causes (just mentioned couple of points above).

Originally Posted by Sutripta

^^^
Begs the question - If it can protect itself, why the (large number of cases of) permanent damage?

I think there is more than one way to answer this question, just taking a shot at them:-

• VW claims that the problems related to the DQ500 gearbox (notorious for most failures and recalls) have been resolved because of the synthetic to mineral oil change. So, as of today, there are no large number of cases reported as such

• The protection of the unit is actually in-built via a feature called as limpsafe or failsafe mode. As mentioned in the "Works" and the "Failures" posts, this translates to the unit avoiding permanent damage to itself. The clutches get disengaged in these modes (resulting in loss/very restricted forward propulsion power).

Originally Posted by R2D2

It's mainly the electronic components and/or actuators in the mechatronics panel that fail

Mostly the actuators and the bushings/valves enabling the gear actuation, essentially the mechanical components inside the unit.

I am not sure to what extent these mechatronics components are affected by high temperatures and if they can do a self-diagnosis for component fault detection at regular intervals. These failures are mostly in tropical and subtropical climates while DSGs experience fewer failures in temperate and northern climes.

You are quite right in your presumption. These components do get affected very much by the high temperatures. In fact, as you can scan the post for "Failures" (link here), temperature sensing is vital.
As for the failures themselves, as quoted in the above link, the initial complaints seemed to originate mainly in S.E Asian countries with typical high humidity, high temperature conditions. However, later on, complaints started pouring from seemingly colder countries like Sweden and the UK also.

In fact being stuffed with more and more electronics has been the bane of EU/German cars, they rarely face mechanical failures. Any resident DSG expert - please correct me if I am wrong.

The research says that only the so-called mechanical components like the bushings, valves, actuator linings, seals, oil, temperature sensors, flywheel drums etc. have been the cause of failures. The electronic control unit, seems to take evasive or programmed actions depending on the failure type. It has, probably, not failed as such by itself.

Originally Posted by Traveler

Clutch dis-engaged translates to pressing down the clutch pedal in a manual shift. When you leave the clutch pedal it gets engaged and transfers power from flywheel to the transmission. Am I correct in my understanding?

The engine power is transmitted from the flywheel to the gearbox first and then to the wheels/transmission.

So if the above it true then the correct way to completely rest the DSG clutches would be to stop the vehicle, put it in neutral, apply the hand brake and then remove one's foot from the brake pedal.
The moment you press the brake pedal the clutch gets dis-engaged waiting for you to slot into "D".

Assuming the ignition is still ON, putting the lever in "neutral" and applying the brake - either hand brake or the main brake, would rest the clutches, yes.
Pressing the brake pedal doesn't have any direct relation with the clutch dis-engagement. However brake pedal pressing energizes the solenoid present in the selector lever assembly and allows you to move the lever to the desired position.

[Traveler]

Originally Posted by JoshMachine

Assuming the ignition is still ON, putting the lever in "neutral" and applying the brake - either hand brake or the main brake, would rest the clutches, yes.
Pressing the brake pedal doesn't have any direct relation with the clutch dis-engagement. However brake pedal pressing energizes the solenoid present in the selector lever assembly and allows you to move the lever to the desired position.

Are we 100% sure that pressing the brake pedal rests the clutch? I think pressing the brake pedal not only activates the solenoid but also the clutch. Since you can slot it into "D" position with the brake pedal pressed.



That means that the clutch is active when the brake pedal is pressed. If the clutch was at rest then we should not be able to slot the gear lever into "D".



On the other hand when you leave the Brake pedal you can no longer slot the gear lever into any position, which also means that the clutch is at rest.



Just my two cents. For what it's worth, I usually apply the handbrake and leave the brake pedal when at a red light. That way I am pretty sure that the clutch is at rest.