# TT RS - strange gearbox behavior



## Shaninnik (Sep 17, 2016)

Hi everyone, I have recently bought a slightly used TT RS with only 10k km on odo. After driving it for a few weeks I have noticed a strange behavior when moving in slow traffic/decelerating. It happens in comfort mode (have not tested dynamic/s) when car is in 3rd gear and I fully release all pedals, letting it roll and stop by itself. When revs approach 800 mark where I expect it to switch to 2nd gear, but instead car jerks a bit, revs jumps a bit over 1000 and it stays in 3rd gear (as if it fails with rev match and does engine braking) and only 1 sec later when revs drop again it smoothly switches to 2nd. This makes moving in a slow traffic a bit uncomfortable. Sometimes this jerk also happens when braking, and I can hear a silent clank. Other then that car is perfectly fine.

This never happened on my regular mk3 TT. Before going to dealership I wanted to know if this happens on other cars and is a normal behavior, or not?


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## powerplay (Feb 8, 2008)

The way the gearbox behaves in the RS has a few quirks but this doesn't sound normal.

What you also describe doesn't make sense as the car will never stop by itself if you just lift off and do not use the brake.

Best thing to do would be to stick a Gopro on the dash and let's see what you're describing, and do try it in other modes also just to be sure - it's only a press of a button so not particularly hard to do!

If you are in 3rd and you lift off the throttle with gearbox in D (and this is from memory) it will shift to 2nd at around or just above 1000 rpm then will (and this is a nasty quirk) dip the clutch too soon and almost coast in 2nd and will then shift to 1st (another quirk) at around 6mph then remain crawling at around 4mph if no brake is applied.

With the gearbox in manual mode and doing the same it will stay in 2nd all the way down to a crawl, as it should do, only selecting 1st if you brake to almost stationary.

Regardless of "mode" there should be no jerking or jumping of revs.

Comfort, auto, dynamic etc has no effect on gearbox operation whatsoever.


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## Shaninnik (Sep 17, 2016)

powerplay said:


> What you also describe doesn't make sense as the car will never stop by itself if you just lift off and do not use the brake


Oops sorry, I meant decelerate, not completely stop. It will crawl as it should if I lift off throttle.

I will try making a video, good idea, thanks :wink:


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## Shaninnik (Sep 17, 2016)

Tried other modes today - not happening in S because it shifts down on higher revs, but what was strange is that it also does not happen in M if a let it to downshift by itself. It goes absolutely smoothly 3 -> 2 and to 1 if I apply brake. So only comfort/D mode is affected. It feels like M is much smoother overall.


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## powerplay (Feb 8, 2008)

I would say I drive mine in manual mode probably 95% of the time and always keep it in individual, never comfort.

i'll try comfort and D on my way to work tomorrow and see how it is.


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## Shaninnik (Sep 17, 2016)

Tried recording it on my phone, sorry for quality - it is a bit shaky, especially when it actually jerks but it is still visible - revs jump up -> down -> up when speed is around 24km/h and then returns to 1000 and slowly go down to 800 when it switches to 2nd (I cut this part). I am not applying brake or throttle, just rolling without doing anything.


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## tt3600 (Apr 8, 2006)

Definitely not normal. Take to Audi to get it checked.


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## powerplay (Feb 8, 2008)

Technically, that be what we call buggered.

Where your revs jump is probably where it would be changing down - but it doesn't?


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## Shaninnik (Sep 17, 2016)

It does not change. It stays in 3rd, changes to 2nd at around 800.


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## powerplay (Feb 8, 2008)

That's definitely not right.

When you accelerate from standstill with light throttle, at what point does it change up 1st>2nd and 2nd>3rd?

In mine it will change from 2nd to 3rd at about 15mph road speed (24kph) and back to 2nd if it slows below about 13mph.

Your revs shouldn't drop below 1000 in 3rd, I think you need to visit your Audi dealer.


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## Shaninnik (Sep 17, 2016)

Thanks for help, will try to get dealer to look at it and see how they can explain this. Hope they will not try to push "standard characteristic of DSG" line. :? Now I know that it's not happening on every car. 8)

Happy new year!


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## Shaninnik (Sep 17, 2016)

Been at Audi today...what they found is that it actually switches to 2nd, but displays 3rd...which is really weird by itself. And ofcourse they said that it is normal because VC will not update gear readings if you don't press any pedal. I think it is total bs. And they failed to explain why car jerks and why it is not happening in manual mode.

So I thought I had one issue (revs jump), but I might actually have two issues - VC is not getting correct gear value from TCU, and car jerks when it downshifts from 3rd to 2nd. Getting OBD11 tomorrow and will try to do a gearbox reset/calibration procedure.


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## powerplay (Feb 8, 2008)

Sounds like something is out of sync or needs calibrating.

Typical Audi dealer BS, just shows it doesn't matter what country or continent!

If you have no luck then I've heard good things about http://www.tvsengineering.nl/nl/ and there are at least a couple of dealers in the US and they have a obd flashing device which I think works for the DQ500, which they have their own "driveability" update for.


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## tt3600 (Apr 8, 2006)

Complain to Audi or take it to another dealer.


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## Shaninnik (Sep 17, 2016)

Did S-Tronic re-calibration process yesterday with obd-11 (Transmission - Basic Settings) -> it still jerks a bit from 3rd to 2nd (more like a slight push), and VC is still shows D3 when it is actually in 2nd, but have a couple of other improvements in gearbox behaviour. I'll leave it for now and use it as excuse to drive in dynamic/S :lol:

Also, this might be interesting, I don't know exactly what dealer did (I bet they don't know themselves if there was a software update) but I am getting more pops and bangs now! It might be a cold weather, or something else... but I really hope not. Exhaust is definitely louder and aggressive now. Had a juicy gunshot while braking before intersection yesterday.


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## powerplay (Feb 8, 2008)

Shaninnik said:


> Also, this might be interesting, I don't know exactly what dealer did (I bet they don't know themselves if there was a software update) but I am getting more pops and bangs now! It might be a cold weather, or something else... but I really hope not. Exhaust is definitely louder and aggressive now. Had a juicy gunshot while braking before intersection yesterday.


Very curious.

Have you already had the official Audi update that removed most of the pops and bangs?


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## Shaninnik (Sep 17, 2016)

I think all cars in north america already had this update. I also have secondary cats (if I am not mistaken only UK and North America cars have them). I am not getting insane amounts of pops, but it is definitely much easier to achieve now - before I had to push it really hard. I really hope that it is not placebo effect. :lol:

I am trying to find Stage 1 ECU with crackles, but without any success - all tuners only offer this on stage 2  But with recent update + secondary cats delete this may be not necessary.


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## macaddict111 (Jun 13, 2018)

For what it's worth, it's actually a more complex process than you'd think for a dual-clutch gearbox to coast or deaccelerate like that. It's akin in a manual to doing the "aborted red light" (i.e. you're coming up to a red light, get to like 10 MPH, light turns green, so then you have to get into 2nd and blip throttle without stopping), but the computer is doing it over and over to keep you in a correct gear as you slow down, but doing it in a way that you don't feel the gear change by smoothly rev-matching, clutching in, and applying just the littlest throttle so you don't feel more engine braking, since you're not on the throttle.

All to say, if something's amiss with any of the sensors or calibration, this is sort of the worst case scenario for a problem to show, since it involves a TON of synchronization between the two gear-trains, wheel speed, engine speed and throttle loading.


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## Shaninnik (Sep 17, 2016)

Yep, thanks for reply. My initial concern was that this was happening while car was in 3rd gear, but after discovering that it actually shifts but simply does not display the change I can now understand why it jerks. I think overall it's my driving habits that I need to change a bit - applying just a bit of throttle or brake instead of just coasting helps.


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## macaddict111 (Jun 13, 2018)

Shaninnik said:


> Yep, thanks for reply. My initial concern was that this was happening while car was in 3rd gear, but after discovering that it actually shifts but simply does not display the change I can now understand why it jerks. I think overall it's my driving habits that I need to change a bit - applying just a bit of throttle or brake instead of just coasting helps.


I 100% agree. This may be your first DSG, and it takes a bit of getting used to. DSG is a LOT more happy if you give it some indication of what you're doing. In your case, if you're even slightly on the brake it will decelerate with both clutches dumped (i.e. coast in neutral) which is how normal people drive a manual, but will keep the 2 next closest correct gears synched but not engaged, so when you do tip into the throttle just a bit it will mesh the correct gear nearly instantly. Likewise if you're coasting with just a little bit of throttle it helps it a lot more. If you're slowing down with no brake, it basically has only one input for what you might want: vehicle speed, which isn't much, and it has to assume you're going to come to a stop. It even takes clues from when you RELEASE the brake, i.e. if you're coasting down to 10, then let off the brake, it'll pre-sync the correct gear as soon as you let off the brake, then it's ready when and if you tip into the throttle.

This is also how and why you avoid the dreaded DSG lag, which is basically when you're coasting to what the compy thinks will be a stop with no brake or throttle, then suddenly floor it. It has no idea where you're headed and it takes painfully long to get in the right gear.


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