DSG issues - thoughts?

[sub39h]

Hi guys,

Not been on for a while so i hope you've all been keeping well. Looking for some help in trouble shooting a problem with my DSG box. I drive a 2006/55 A3 2.0T that has about 97k on the clock (75k in my ownership). It's had all its DSG services on time or early and was last serviced last summer at an Audi main dealer. All my other mechanical work for the last 5 years or so has been carried out by Alex at AKS.

Around winter time it developed a fault. Was like a flick of a switch. One day the fault wasn't there and the next day it was. It only affects even gears under partial load. I'll get a sort of surge in the revs and a nasty vibration through the whole car. It's very replicable but doesn't seem to be as bad some times as others. There doesn't seem to be any clear pattern as to why it might be worse some days and better on others.

It's reasonably noticeable in 2nd gear, much worse in 4th and only very slightly noticeable in 6th. If I'm travelling at sensible motorway speeds up a hill around 3k rpm - you'll see the Rev needle go up maybe 100rpm, and back down again over about a 2 - 3 second cycle. In 2nd and 4th around 1200 and 3000 rpm the revs will surge and you feel the vibration.

Sometimes the change from 1st to 2nd and 2nd to 3rd can be particularly harsh as well, making the car quite unpleasant to drive in stop start traffic. But then sometimes it's not too bad.

I did a DSG reset as I'm a VCDS owner, it seemed to soften the problem at first (though it never went away) and then it came back just as bad as it was before.

I thought it might have been a mechatronics problem but then I wondered why it would only affect even gears. Then I thought about the clutch but then wondered why it was only happening in certain parts of the Rev range, and why it was sometimes worse than others. Then I thought maybe the mounts were perished and at a certain frequency they were vibrating causing the problem but this seems fairly unlikely to me. I also thought maybe it was to do with the throttle but again seems unlikely as it only affects even gears.

Does anyone have any suggestions on what it may be? I don't live too far from R-Tech and was thinking about getting a remap from them but I want this issue sorted first. I'm considering calling them on Monday and seeing if they have any time to maybe do a mini diagnostic because they've been incredibly helpful in the past but was wondering if any of you knowledgable people had any other suggestions first.

Thanks in advance chaps 

[amanda]

That sounds like the box on the way out 
Best thing you can do is best take it to an auto box place for a check up......you might be lucky and find the fluid is low!

[sub39h]

Lol hopefully it'll be something that simple! Unlikely tho because the box was serviced by a main dealer less than 12 months ago!

Been looking around for other sources of DSG problems at this sort of age. Seems the DMF is one but I don't have any "pebble in a washing machine" type rattles, no juddering at idle and as I said it only affects even gears!

I just did another DSG reset and the gesr changes do seem much smoother, but still have the juddering when under partial load.

[dajonic]

Sounds like the clutch packs need replacing as one clutch looks after the even gears and the second the odd gears and reverse i think. Had a similar issue with mine a while ago where I noticed the revs hunting slightly on "cruise control" while on the motorway. Replaced the clutches and the dual mass flywheel at the same time and problem solved. I'm surprised by the low mileage on yours for this to happen though, has it had a hard life? From memory about £550 all in?

[sub39h]

Thanks very much - was worried it might be the clutch but as you said didn't think this would be a problem on such a low mileage car. Also I would have thought a clutch problem would have been more consistent, similarly apparent in all gears and through more of the rev range?

Car's not had a particularly hard life, no. A lot of motorway miles. I'm a fairly sedate driving 29 year old. Never been on a track. Only been launched maybe a handful of times in the 6 years I've owned it.

[doylebros]

How long does the vehicle have to be running before the fault appears, is it straight away or after a few hours motorway driving then entering an urban area etc?

[sub39h]

Straight away

[doylebros]

Straight away

Since it's straight away that's not one I've had so will have to pass on that one I'm sorry to say.

[dajonic]

Maybe get it booked into R-Tech as my problem only showed itself set on cruise and at motorway speeds so maybe a little bit more to it with your situation? Definitely sounds like clutch packs and fly wheel though, good luck with the fix!

[sub39h]

Straight away

Since it's straight away that's not one I've had so will have to pass on that one I'm sorry to say.

Just out of interest what are you thinking please?

[vag]

Sounds like clutch packs the repair kit is just under £400 so not the end of the world if it is. You could send your mechatronics to ACtronics to be tested which only costs around £60 just to make sure

[doylebros]

Straight away

Since it's straight away that's not one I've had so will have to pass on that one I'm sorry to say.

Just out of interest what are you thinking please?

I'm think what VAG posted would be line of thought and the way forward.

[sub39h]

Ok that's not as bad as I expected - I'll call R-Tech and see if they're up to helping confirm the diagnosis for me, and book it in with Alex for a fix. £400 isn't as bad as I thought. Still not ideal though as it's a fairly hefty portion of the value of the car!

Thanks for all your replies folks!

[sub39h]

Ok R-Tech didn't have time for an RR diagnostic, and they said they'd probably not find the problem anyway.

I tried another DSG reset which softened the problem again.

Then yesterday whilst procrastinating from revising for an exam I have next week I watched a Fifth Gear video which amongst other things tested out Redex petrol system cleaner and managed to get 4bhp (5%ish) back from an old car. It's only £4 from Wilko so I decided to try it out (not for the gearbox, just because it's so cheap I thought why not).

Tonight I couldn't replicate the problem anymore. I'm gonna see how it goes the next few days but it's been having those symptoms for months so it's bizarre they've suddenly gone. Maybe it was some sort of fuel line related misfire, but I'm not going to bank my hopes on it until after a few more days driving.