EZES

Good evening, guys! I own a 2016 Audi A4 B9 Sedan with S-tronic gearbox, aprox 200k km. Last night while I was driving around I noticed that my car makes some sort of whistling noise when in 5th gear, especially while accelerating. It does not seem to make the same noise when in other lower gears and not in 6th or 7th gear. I am a bit paranoid about the gearbox failing to be honest, although I do not know yet if the problem is because of the gearbox. I was wondering if any of you had similar issues and perhaps can share with me what the problem was. I also put a link of a video I took so you can clearly hear what the noise is like. Thanks!

Link to video

A4Audi4Fun

Sorry can't hear anything. If it's really a net new noise, suggest you take a look at your window seals, door seals and mirror housings in case there's some dirt or something that is affecting the normally very smooth airflow of our cars.

142 guy

I am equally deaf. What is the time stamp in the video when the noise occurs?

EZES

It's in the entire video.. it's like a high-pitched whistling noise.

Airfan

I hear it very well. Better make video starting from 4th then going up to 6th so all can hear the difference. Unfortunately I don't know what is causing the noise but if it is on 5th gear only then it has to be related with the transmission.

142 guy

If I crank my monitor speaker volume up to maximum, I can just hear a whine / whistle. It doesn't sound like gear noise or bearing noise; but, the position of the recording microphone may not be picking up exactly what you are hearing.

If the noise just occurs in 5th gear, when the noise is present listen while you apply the throttle and then let off the throttle (coast). If the noise disappears when you coast you could have a problem caused by wear on the 5th gear pair. With the transmission in 5th gear in manual shift mode, check for the presence of the noise over a large RPM range. If the noise is present over the full range RPM range and increases with RPM then that also points at a problem with the 5th gear pair. If the noise is only present at a certain RPM which corresponds to a certain speed I don't think that is gear pair noise. More likely a wind related noise of some kind.

There were reports of output bearing noise on some higher mileage S tronic transmissions. However, output bearing noise would be present all the time and typically gets louder as vehicle speed increases. Bearing noise also tends to sound more like a howl until it becomes terminal when it turns into a grinding / scraping noise.

EZES

Well, I just went to a mechanic and ask a couple of friends who are also mechanics and determined that it is probably not the gearbox. The sound starts in 4th gear at around 1800rpm and stops somewhere above 2000 something rpm. Does it in 5th and 6th gear as well and probably in 7th gear also but because of the high speed in 7th gear and all other noises it is hard to determine. My mechanic said it is probably the turbine and not the gearbox. He also put it in manual and in 5th gear at lower rpm there was no noise. He said the whistling noise the car makes is specific for turbines and that I should not change it until its time comes. I will go to a garage that only deals in automatic transmissions and see what they have to say. My mechanic also recommended that when I go on the highway I use a lower gear at higher rpms to help the turbine clear itself so will probably do that and hope for the best. Still hope it's not the transmission tho'.

Airfan

When you hear the noise if you put it to N does the sound stop? If yes - it is something with the engine or turbine - if it doesn't - it is something with the insulation or something that is moving while coasting.

EZES

The noise seems to stop once I take my foot off the gas pedal.

Airfan

Then I would check the turbine (you should be able to hear it well if you rev the car stationary) if not the downpipe and the exhaust, then the belts and pulleys. After that I am out of ideas.