Audi A7 Tdi quattro - jerky and erratic clutch gearbox but no codes on VCDS!

[Mad4adino]

I have an Audi A7 3.0tdi quattro (2011 MY) with 7 speed gearbox, which in last few weeks has been giving me some weird experiences:

- when coming to a standstill at a junction, get a surge from the engine causing car to jump forward a little

- At lower speeds in D3 and lower revs can feel throttle pulsing, see rev counter jumping up and down, also slight similarity when in D5

- noticeable clunk when gear changes from D2 to D1

- if driving hard can feel gear knock/clunk occasionally as gears change up

I have had car to two different techs using VCDS/ODIS and both times no faults appearing at all, despite driving issues above.

car has 104k, Gearbox oil was changed at 50k (know needs doing again)

Gearbox oil levels all good, no leaks

have car booked in end of week for a glycol test in gearbox as next steps diagnostic

looking for any ideas that make sense despite no codes

 

 

Edited February 13, 2022 by Mad4adino
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[Stevey Y]

10 minutes ago, Mad4adino said:

I have an Audi A7 3.0tdi quattro (2011 MY) with 7 speed gearbox, which in last few weeks has been giving me some weird experiences:

- when coming to a standstill at a junction, get a surge from the engine causing car to jump forward a little

- At lower speeds in D3 and lower revs can feel throttle pulsing, see rev counter jumping up and down, also slight similarity when in D5

- noticeable clunk when gear changes from D2 to D1

- if driving hard can feel gear knock/clunk occasionally as gears change up

I have had car to two different techs using VCDS/ODIS and both times no faults appearing at all, despite driving issues above.

car has 104k, Gearbox oil was changed at 50k (know needs doing again)

Gearbox oil levels all good, no leaks

have car booked in end of week for a glycol test in gearbox as next steps diagnostic

looking for any ideas that make sense despite no codes

 

 

Hi try cleaning the EGR as they are prone to playing up and not throwing codes up, if thats not working properly that would cause the first symptom as the EGR failing will fill the throttle body with gunge so it can't get to the required position quickly enough, the throttle body normally only throws a code when it starts to get well and truly stuck.

Steve.

[Mad4adino]

13 hours ago, Stevey Y said:

Hi try cleaning the EGR as they are prone to playing up and not throwing codes up, if thats not working properly that would cause the first symptom as the EGR failing will fill the throttle body with gunge so it can't get to the required position quickly enough, the throttle body normally only throws a code when it starts to get well and truly stuck.

Steve.

Thanks for taking the time to respond Steve, will look into that, had friend suggest getting a TerraClean done on the vehicle but wanted to see if anyone had experience of having it done?

cheers David

[Stevey Y]

7 hours ago, Mad4adino said:

Thanks for taking the time to respond Steve, will look into that, had friend suggest getting a TerraClean done on the vehicle but wanted to see if anyone had experience of having it done?

cheers David

Hi don't bother with terra clean as I have known people to have that process and still end up replacing the offending parts, if you look at it it logically if you clean the EGR and throttle body and one or both items especially the EGR are worn out the cleaning won't cure that problem you still have to buy a new unit that way you have lost the money for the cleaning and the parts, these things are all good if done regularly from new, my advice would be clean what you have and see what occurs.

Steve.

[Dazza297]

Hi I have the exact same issue between d1 and d2.. I know its not the gears themselves as in manual mode they operate perfectly. Just wondering if you got a resolution? 

[Mad4adino]

20 hours ago, Dazza297 said:

Hi I have the exact same issue between d1 and d2.. I know its not the gears themselves as in manual mode they operate perfectly. Just wondering if you got a resolution? 

Hi Dazza297

i ended up getting the mechatronic repaired with the Audi repair kit, cost about £1000 all in, resolved issues but it’s a very common issue on this gearbox (only issue is that the OEM part has not been modified so only time/100k before it goes again)

HTH