S-tronic downshift behaviour

[aro03]

Hey guys,

I recently had my S4's mechatronic circuit board replaced under TPI 2022497/18. Since then the car generally drives far smoother, but i'm still worried that my gearbox isn't operating properly. I have read all the DSG problem threads and taken what I can from them. However I've never had the chance to drive another S4 or s-tronic equipped audi, so i'd really appreciate your thoughts/experiences on my DSG symptoms:

The problem i'm having is with a specific type of 3-2 downshift. It might sound at first like the typical DSG jerkiness, but because that disappeared after the mech circuit fix i think it might be something else. What happens is that the downshift between 3-2 pauses longer than usual before clutch engagement (pause is probably 0.5s, but feels longer), followed by a harsh and very rapid clutch engagement. It isn't quite as bad as being rear-ended and it doesn't 'clunk', but it sticks out like a sore thumb compared to 'normal' shifts.

However this symptom happens ONLY during a specific combination of driving conditions and accelerator inputs. Roughly like this: coasting down off throttle (or braking) as the downshift initiates, combined with getting on the throttle BEFORE the clutch engages 2nd. This is a frequent scenario driving where I live - say turning off a main road, coasting up to a light which then turns green etc. It happens occasionally in sport/dynamic, but i can also consistently replicate it in manual mode.

Although i wouldn't normally shift in this sequence under manual control, it can't be avoided in automatic mode. Can someone else try this out on their S4 to see what it does?

1. Coasting or braking lightly in 3rd (off throttle), let engine speed drop to roughly 1500-2000 rpm.
2. Downshift to 2nd (still off throttle).
3. Just after shift initiates (i.e. gear indicator changes in dash) BUT BEFORE the clutch engages get on the throttle (not flooring it but with clear intent to pull away).
4. DSG seems to pause (maybe 0.5s longer than normal shift but feels like forever when trying to accelerate), then engages the clutch harshly and takes off.

The pause is what makes this downshift really annoying, because you feel like the car is stalling just before it takes off. It happens to some extent for any gear combination when following this order of shift & throttle inputs, but in my car 3-2 is the most harsh. Sometimes the pause is slightly shorter, sometimes slightly longer - feels pretty random but when you get a long one it is really annoying.

Has anyone else experienced this (or does your car not do it)? If anyone would be willing to try this out on their DSG and get back to me i'd be really grateful.

thanks

Ant

Couple pics from after the repair:

 

[GeoffDunk]

THis does seem strange, mine is instant as gears 1,3,5,7 are on clutch 1 and gear 2,4,6 are on the clutch 2 and between odds and even gears the change should be pretty much instant (100ths of a sec).

Mins is a 2015MY RS$ but the principle is the same.

 

[skiptowncat]

Mech unit will learn your driving style, maybe they didn't do the adaptation drive after replacement

 

[aro03]

Mech unit will learn your driving style, maybe they didn't do the adaptation drive after replacement

The dealer actually let me do the adaptation drive...shifts definitely improved over the first hundred miles but it seems to have settled now.

 

[skiptowncat]

Did they update it to the latest software?

 

[aro03]

I believe so yes.

 

[GeoffDunk]

All,

S-tronic (DSG) boxes from the VAG group do not learn your driving style, any dealer that tells you they do doesn't know the product.

This is worth while reading and I have a very close friend who is Business Development & Senior Area Manager for Oerlikon Graziano Trasmissioni who is also confirming the validity of this information.

http://vwcaliforniaclub.com/threads/dsg-delay-before-pulling-away.8447/page-2

or here

http://forums.vwvortex.com/showthre...-DSG-Game-and-Win-DSG-Driving-Tips-and-Tricks

He's looking into the "adaptation drive" to understand what the dealers mean by this.

For those who don't know the name, Oerlikon Graziano, their transaxles and gearboxes are standard fitment in cars produced by Aston Martin, Ferrari, Lamborghini, Maserati, Alfa Romeo, Audi and the most recently announced new cars to feature their transmission systems are the Aston Martin One-77 and Vantage S, the McLaren MP4-12C & P1 and the Lamborghini Aventador. They also write the software for the standard geaboxes including the S-tronic for the B8.

I hope this helps and I'll get back to you with further info straight from the horses mouth.

 

[razza1]

The adaption drive is simply teaching the unit the shift points for each gear.
It doesn't learn your style, it adapts to limit wear on the parts

 

[aro03]

The adaption drive is simply teaching the unit the shift points for each gear.
It doesn't learn your style, it adapts to limit wear on the parts

That's what I had understood as well. Will go check out those links though, thanks guys.

Would be great if anyone has a chance to try that downshift sequence i described...maybe on their way to work tomorrow?

 

[razza1]

If I remember I'll try. I had the details of the adaption drive somewhere as tried it on mine before the mech unit replacement. Helped smooth it a bit, kind of resets the behaviour of its gone off. Will see if I can find it again.
After changing the unit they had to do the adaption drive. I'm surprised he let you do yours though as it needs to be done when the oil is at a set temp, which is a difficult temp range to do it on, my Indy guy was saying how the golfs etc have their adaption when it was fully warm, vs this which was around 60 degrees from memory (but may have that wrong as trying to recall a conversation before Xmas)

 

[GeoffDunk]

I did this evening in my RS4 and shifts are as good as instant as expected. I also tried it in confort mode and still they were very instant.

I tried also sort of simular scenarios and all changes were instant, not sure if the 7 speed S-tronic on the RS4 is different in any way though.

 

[aro03]

All,

S-tronic (DSG) boxes from the VAG group do not learn your driving style, any dealer that tells you they do doesn't know the product.

This is worth while reading and I have a very close friend who is Business Development & Senior Area Manager for Oerlikon Graziano Trasmissioni who is also confirming the validity of this information.

http://vwcaliforniaclub.com/threads/dsg-delay-before-pulling-away.8447/page-2

or here

http://forums.vwvortex.com/showthre...-DSG-Game-and-Win-DSG-Driving-Tips-and-Tricks

He's looking into the "adaptation drive" to understand what the dealers mean by this.

For those who don't know the name, Oerlikon Graziano, their transaxles and gearboxes are standard fitment in cars produced by Aston Martin, Ferrari, Lamborghini, Maserati, Alfa Romeo, Audi and the most recently announced new cars to feature their transmission systems are the Aston Martin One-77 and Vantage S, the McLaren MP4-12C & P1 and the Lamborghini Aventador. They also write the software for the standard geaboxes including the S-tronic for the B8.

I hope this helps and I'll get back to you with further info straight from the horses mouth.

Thanks for the links, both of those threads have some really good tips for dsg driving and I have seen them before.

Just to clarify I don't get any delay pulling away from stationary.

Also I realise the shift sequence I described is exactly the opossite of he recommend dsg techniques you linked to - and I manual mode I wouldn't purposely drive like that. Problem is that in auto mode you can't avoid doing it occasionally. for example roundabouts, turn offs, traffic hazards etc occasionally require getting on the throttle before the clutch has fully engaged...

Would be great if I could just sit in or drive another s4 to see how it behaves as this kind of dsg symptom is highly subjective.

 

[aro03]

I did this evening in my RS4 and shifts are as good as instant as expected. I also tried it in confort mode and still they were very instant.

I tried also sort of simular scenarios and all changes were instant, not sure if the 7 speed S-tronic on the RS4 is different in any way though.

Thanks Geoff that's really helpful to know. If the consensus is similar then I'll be heading back to the dealer to arrange a drive with a tech.

 

[razza1]

Can't find it, might be on my work laptop so will check tomorrow

 

[razza1]

Not sure if you are aware also, you don't need to be in manual mode to use the paddles. Even if in auto if you think you'll want to accelerate you can drop down a gear with the lever. After s short timeframe it will go back into auto mode

 

[skiptowncat]

Not sure if you are aware also, you don't need to be in manual mode to use the paddles. Even if in auto if you think you'll want to accelerate you can drop down a gear with the lever. After s short timeframe it will go back into auto mode

^^this^^
I've found to be the best way to drive it when I know I'm going to need to squirt the power (like an overtake) is to either, press the pedal about 60% and hold, just dropping back off the pedal slightly to hold the gear without accelerating or just do it manually and have the correct gear pre-selected

 

[aro03]

^^this^^
I've found to be the best way to drive it when I know I'm going to need to squirt the power (like an overtake) is to either, press the pedal about 60% and hold, just dropping back off the pedal slightly to hold the gear without accelerating or just do it manually and have the correct gear pre-selected

I agree this is a better way to drive the dsg. I dont have jerks or pauses if im on the throttle when the downshift initiates.

What I'm still trying to work out is whether my dsg box has an issue. The downshift sequence I'm describing is just an example that best illustrates the symptoms.

 

[skiptowncat]

I'll try and replicate on the way home tonight

 

[razza1]

My 3-2 is fine, my 4-3 is very clunky and quite harsh

 

[aro03]

My 3-2 is fine, my 4-3 is very clunky and quite harsh

Thats interesting...my 4-3 is pretty smooth, even when i try and make it harsh.

Is your 4-3 always a rough shift, or just when you try the downshift sequence i described?

 

[razza1]

Always. It's since they put in the second mech unit (1st one didn't solve my issues), the master tech reckons it's because it's been disturbed a lot so more gearbox than mech unit now. 2-1 is also a bit crap. No issues at all going up, you don't even notice the changes

 

[ub7rm]

Could this just be that you've tricked the car with your intentions?

As I understand it it preselects the next gear based on your driving history - i.e if you are slowing down it will preselect the next lower gear on the other shaft meaning its instant and smooth when it does have to change down. I've noticed it can be a little confused when I'm slowing down then hit the throttle again - there is every so slightly more delay because instead of needing, say, 2nd which it thought I would need and thus preselected it in readyness it has to drop that and pick up 4th.

The circumstances this happens in are quite rare - and I have to say there is no harshness about it - just an ever so slightly longer delay than when its just working up or down the box.

One thing I have noticed is when I boot it the revs rise, and nothing, then the clutch engages on the lower gear and it shoots off. For all the internets chat of 'instant' S-tronic gear changes I was surprised at the delay (probably a second or so). Again I think its do do with selecting the gear - in kickdown it will drop 2 or 3 gears which I guess means it is choosing another gear on the same shaft as it was originally on. Used to it now

 

[aro03]

Could this just be that you've tricked the car with your intentions?

As I understand it it preselects the next gear based on your driving history - i.e if you are slowing down it will preselect the next lower gear on the other shaft meaning its instant and smooth when it does have to change down. I've noticed it can be a little confused when I'm slowing down then hit the throttle again - there is every so slightly more delay because instead of needing, say, 2nd which it thought I would need and thus preselected it in readyness it has to drop that and pick up 4th.

The circumstances this happens in are quite rare - and I have to say there is no harshness about it - just an ever so slightly longer delay than when its just working up or down the box.

One thing I have noticed is when I boot it the revs rise, and nothing, then the clutch engages on the lower gear and it shoots off. For all the internets chat of 'instant' S-tronic gear changes I was surprised at the delay (probably a second or so). Again I think its do do with selecting the gear - in kickdown it will drop 2 or 3 gears which I guess means it is choosing another gear on the same shaft as it was originally on. Used to it now

Based on the downshift sequence i described, i don't think the delay I'm experiencing is due to the box not having the right gear preselected.

It is useful to hear that you occasionally experience a similar delay just without the harsh transition.

I also get the short delay you describe when flooring it. The revs build whilst the box downshifts several gears, then engages the clutch smoothly. That is pretty normal operation as far as I'm aware.

 

[skiptowncat]

Didn't get chance to test this yet

 

[aro03]

Didn't get chance to test this yet

No worries, appreciate all your guys help alot.

I was mesing around again on my way home and realised that the shorter the delay between pulling the paddle for a downshift and getting back on the throttle, the longer the delay before clutch engagement.

It's really strange. Like I was saying earlier, if im already on the throttle when I downshift then there's little to no delay and a nice smooth transition

 

[skiptowncat]

No worries, appreciate all your guys help alot.

I was mesing around again on my way home and realised that the shorter the delay between pulling the paddle for a downshift and getting back on the throttle, the longer the delay before clutch engagement.

It's really strange. Like I was saying earlier, if im already on the throttle when I downshift then there's little to no delay and a nice smooth transition

That's because the gearbox will have the correct gear pre selected. Normally it will line up the next higher gear for economy purposes

 

[benjie]

I really don't want to tempt fate, but hey. I have an 09 DSG that is still on it's original mech unit. I'm working on the premise that it would've gone by now if it was a dud, car's approaching 80k. It has had the circuit board recall though.

I find 3-2 rather annoying. It is jerkier than all the others, but only by a tiny fraction, not enough for anyone to notice but me - I'm tuned to the box from all the horror stories! What annoys me is, like the OP said, you can be coasting from just below 20 in 3rd and slowing down. The car stays in 3rd down to something stupid like 8mph, far too slow for 3rd gear and the car knows it. My car's threshold for dropping from 3rd to 2nd is 12mph (yes, I notice these things!) so at 11/10/9/8/7mph etc when I am off the power and slowing, the car knows that 3rd just won't cut it but it keeps it there. Then when I apply the throttle, it then shifts into 2nd giving me a tiny delay, almost imperceptible, but it's there. I hope you understand what I'm on about.

I think it's done for smoothness, but I'd rather it changed to 2nd at the threshold so I can have the gear ready to go... I suppose that's what Dynamic mode is for.

 

[aro03]

I really don't want to tempt fate, but hey. I have an 09 DSG that is still on it's original mech unit. I'm working on the premise that it would've gone by now if it was a dud, car's approaching 80k. It has had the circuit board recall though.

I find 3-2 rather annoying. It is jerkier than all the others, but only by a tiny fraction, not enough for anyone to notice but me - I'm tuned to the box from all the horror stories! What annoys me is, like the OP said, you can be coasting from just below 20 in 3rd and slowing down. The car stays in 3rd down to something stupid like 8mph, far too slow for 3rd gear and the car knows it. My car's threshold for dropping from 3rd to 2nd is 12mph (yes, I notice these things!) so at 11/10/9/8/7mph etc when I am off the power and slowing, the car knows that 3rd just won't cut it but it keeps it there. Then when I apply the throttle, it then shifts into 2nd giving me a tiny delay, almost imperceptible, but it's there. I hope you understand what I'm on about.

I think it's done for smoothness, but I'd rather it changed to 2nd at the threshold so I can have the gear ready to go... I suppose that's what Dynamic mode is for.

Really useful info thanks mate. Sounds like similar behaviour to mine but slightly smoother.

 

[V6 Quatt]

Lets all get together and try each others out!!!!

 

[aro03]

Lets all get together and try each others out!!!!

Would definitely be up for a meet, even if only as a passenger. Anyone else nearby reading/West London?

I'm going for a test drive with a tech at the dealer tomorrow - should be interesting.

 

[V6 Quatt]

its worth it if all us guys can get together even for a meet drive and a beer or orange juice!!??

 

[razza1]

Would definitely be up for a meet, even if only as a passenger. Anyone else nearby reading/West London?

I'm going for a test drive with a tech at the dealer tomorrow - should be interesting.

Which dealer? I'm working from home tomorrow in reading so could certainly fit in a sly comparison test drive

 

[razza1]

And you can even see what stage 2 feels like

 

[aro03]

And you can even see what stage 2 feels like

That's what i'm afraid of....I won't be able to put off tuning any longer after that!

Tomorrow i'll be at Guildford Audi around 11 am - unfortunately I've got a hectic afternoon so I can't really do anything.

I'm definitely up for an S4 meet though. I'm free most weekends - Razza, V6Quatt, when/where would be good? Anyone else?

 

[V6 Quatt]

Busy tomorrow...Lets make a weekend meet and get some guys together for a rant

 

[aro03]

Just an update on the situation....

The test drive with a master tech revealed that
- The car occasionally exhibits clunking in 2-1 shifts which is NOT normal
- Downshifting from 3-2 should be smooth, regardless of any delay.
- Delay during the manual down shifting sequence i described wasn't a cause for concern

Based on the first point alone the dealership agreed to replace the clutch packs and complete mechatronic unit. I had noticed this slight clunking but it was so smooth compared to before the repair I thought it was just normal operation.

In the meantime I was given a 64 plate A-7 s-tronic 3.0 tdi as a loan car! The first thing I noticed is how much smoother its gear changes are. I didn't realise it was an s-tronic until I got it home! Perhaps this is partly due to design, but I also wouldn't be surprised if the s-tronic units are improving.

Interestingly, it also exhibits the slight pause during the downshift sequence i described.