Jerky acceleration in Audi S5 V8 with 6-speed Tiptronic

Hello,

My name is Jörg, and I signed up because I maintain and repair my own vehicles and occasionally need some advice.
I haven't trusted repair shops for a long time now.

Last year, I bought a 10-year-old S5 with a 4.2L V8 engine from an Audi dealership.
The car now has a mileage of 76,000 km, so it hasn't been driven very much.

Regarding the issue:

I'm posting this in the "Transmission" section because I suspect the problem lies there.
The error occurs sporadically and only during cold starts; it cannot be attributed to a specific outside temperature or similar factors.
The fault memory was read using VCDS... and there were no entries.

Upon cold start, the engine starts perfectly and runs at an idle speed of approximately 1100 RPM.
Until then, everything will be fine.
After pressing the brake pedal and shifting into reverse, a noticeable drop in engine speed occurs, but the engine still runs smoothly and evenly.
When driving mode "D" is engaged, the engine speed fluctuates within a range of 500 RPM, which might lead one to believe that the engine is about to stall.
When the foot is taken off the brake, the car starts to move, but it jerks violently because the engine speed fluctuates dramatically.
With a slightly higher RPM, the jerking intensifies until it completely disappears after a few moments.
As mentioned before, the problem only occurs sporadically and only during cold starts.

The car still has a used car warranty from VVD, so I won't be able to do much right now.
I want to avoid countless trips to the workshop where nothing ever gets resolved except for a lot of empty promises and excuses... etc.

The only thing I'm going to do is check the transmission fluid level.

Perhaps some of you have heard of this problem before, or maybe someone has advice that I would be grateful for.

Hello,

I just checked the transmission fluid level according to the repair manual.
Starting at 35°C, with the engine running, the inspection screw was opened. At this point, ATF (Automatic Transmission Fluid) should start to leak out up to a temperature of 45°C. However, nothing happens. Only starting at a temperature of 50°C does the ATF begin to drip out.
So, it's probably because there isn't enough oil in it?
Unfortunately, I am unable to assess whether it has those effects.

Hello,
Not enough oil can make a big difference. I would definitely top up the oil first to rule that out and prevent potential damage to the transmission.

Best regards,
Dago

Thank you for the response.

I'll probably switch to a completely different product. But first, I need to check with Audi about what they will do regarding the warranty. I read on the ZF website that it should be replaced every 100,000 km or after 8 years. At Audi, they say it's a lifetime fill.

I noticed something else today.
At the traffic light, in driving mode D and with my foot on the brake, I felt a jolt in the vehicle, similar to what happens when the transmission tries to shift while stationary.

I then went to the mechanic. He read the error codes, but there were none.
He also believes that the oil should be refilled or changed.
The oil has been drained and the oil pan has been removed. I'm still waiting for the oil change kit from ZF.

Please provide a brief update on the issue.
After the oil and filter change, the problem no longer occurred, or is only barely noticeable.
Only an oil change was performed; no flushing was done.

Thank you for the feedback!

Please provide a brief update on the issue.
After the oil and filter change, the problem no longer occurred, or is only barely noticeable.
Only an oil change was performed; no flushing was done.