pixo.sk

Hi guys,

I am quite depressed by this so seeking some help on forums.

DL501 harsh downshift in 2014 A6. Occasional 3-2 when specific conditions are met and almost every 2-1 once hot.

No errors, which drives me mad.

My fixing procedure to date was as follows:

1. Changed oil and both filters (still harsh)
2. Changed all solenoids in mechatronic, new harness (except those in “tower” related to forks) (still harsh)
3. Changed dual-clutch, flywheel, all gaskets, new bearing - now still waiting to finish clutch point calibration (100km driven, however already harsh)
4. This only happens when the engine/transmission gets hot. Its worst when hot and agressive stop is made at the same time.

Otherwise its silky smooth including all upshifts 1-7 and downshifts 7-3. No kicks at stop in D or R. Every gear follows order as it should, no skipping.

I am now waiting for Audi Dealer to get an software update if available (not sure if they will do it but I have only VCDS/VAG-COM). According to this article it may help but does not makes sense for me as everything has already been changed (https://www.transmissiondigest.com/shock...-release/#)

As I am a little bit skeptic this will help I am proactively looking for next steps I can take. Any ideas please?

Its my own car in totally superb technical shape at 225 000km. No issues from new until approx last 1000km when kicking starts.

Thank you for any advice.

Transmission identification data:
Part No SW: 4G5 927 156 HW: 0B5 927 156 K
Component: 0B5 30 TDIRdW H02 0003

last_mile

Hey

Any update on your case? I am also facing similar issues for my '13 A6. Mine is more like a strong jerk after downshifting 2-1 when coming to stop slowly. Only happens once hot. Doesn't occur if i downshift to 1 early manually. Also, the jerk is not happening if i make a quick stop. Occurs only if I let the transmission gradually downshift to 1. The 3-2 jerk is occasional in my case too.

pixo.sk

Hi, now waiting for the oil pump and bearing to get it done. Pity that transmission has to go out once again which is quite a job. I will update you if it help but may take week or two.

The problem in my case is that from the start there weren't any fault codes in VCDS. Just jerk in 3-2 and mostly 2-1. I made a full adaptation via VCDS once again and it helped a little especially for 2-1 but its still definitely there and 3-2 suprise me once in a while too.

If the pump wont help I am lost but specialists were quite confident it will help. Anyway there is not much else that left as I've change a lot already. Fingers crossed.

pixo.sk

I now waiting for parts to come. Audi refused to do an update as there is no error logged in TCU, so they I unable to do it. However I may found a local independent to perform it. Once that will be done (and if it won't solve the issue) I will replace the transmission oil pump and bearing for k2 shaft. That may take few weeks until I get it all aranged. I will update you after that - hopefully with final solution.

last_mile

I really hope your diagnosis is accurate and that the procedure will fix it for good. Looking forward for your post update.

S4'ed

Did you check these valves in the valve body? The bores tend to wear and then the piston O-ring doesn't seal properly. There are kits to cut the bore to a slightly larger diameter, and then replace the piston and O-ring with a larger verson.

pixo.sk

Thanks for update. I have already seen this. However pity is you need a tool for 200 EUR to make space for oversized valve. The valve itself is like 10EUR.
Not sure where to get original size valve if event possible to change it this way (without a tool)

Otherwise no new update yet as I have didn't time to arrange things, however one new strange finding:

On S the occasional 3-2 downshift did not hapen ever. In D in certain conditions like temperature, quick stop, etc. it happens especially when oil is hot. In S never, event when is hot. However 2-1 still present even in S.

pixo.sk

SOLUTION

Hi guys, I am very sorry you didn't hear from me sooner. However, it was the craziest month in this year for me. Personally and at work.

Finally looks like the problem is solved and the last issue in was really a damaged gasket on valve body as was suggested. Image from my issue attached. I must missed that first time.

I also managed to up to date SW version of TCU as mentioned below.

Few kilometres at oil temp approx 90 degree celsius, finished adaptation and 2-1 didn't kicked once.

So just to sum it up for anybody that will be in the same boat:

- new oil, both filters, gasket
- change all the solenoids at the bottom of the mechatronic
- changed dual clutch pack, flywheel, bearing
- software update to v 005 (this alone solved occasional 3-2 harsh downshift, and the transmission does not select D1 until I am at complete stop now)
- changed the mechatronic gasket at valve body
- adaptation

Thank you for all your advice. Really appreciated.

S4'ed

Not clear to me from the pic, but what exactly is the damage of the gasket?
And where did you get info that the gasket might be the problem?

pixo.sk

I have made a mockup for you to better understand the location.

The issue is the gasket there is missing (burned, weared off or whatever) and that affects the pressure there. Especially with the higher viscosity of oil once hot. This factor may affect the pressure, operation of valves and thus the operation of mechatronic unit and transmission.
But thats just my simple theory.

The facts are now:

1. the gasket should be there and is not
2. the transmission now drives without harsh downshifts 2-1

If I will enconuter the problem again, I will report back.
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