Audi A6 whistling/whirling sound when accelerating

[NeroRapid]

Hello everyone,
I own Audi A6 (C7) 2.0 TDI Ultra S-Tronic from 2016. I hear whistling/whirling sound when accelerating slowly or harder from 60 mph/70 mph at 4th, 5th, 6th or 7th gear even if I drive slower and want to accelerate this sound is hearable from front of the car. The sound comes from left/centre/front side of the car and is noticeable behind the dashboard. When I switch gear on neutral when driving is quiet also if car is stationary on parking gear to do revving nothing is happening as well. The sounds appearing only when accelerating not when revving. Thank you

Links to video:

 

[abmat]

I’m sorry but I can’t make anything out.

could be turbo failing, belts, tensioners, pulleys, gearbox(as it happens under load).

 

[NeroRapid]

I’m sorry but I can’t make anything out.

could be turbo failing, belts, tensioners, pulleys, gearbox(as it happens under load).

Hello,
Mechanics struggling to diagnose what is this. It's happens no matter I drive on my own or under load with passengers or baggage.

 

[abmat]

Sorry. By load I mean’t with drive/torque going through the gearbox as it doesn’t happen when in neutral.

how many km has the car done and has the gearbox oil ever been changed?

 

[Garrett 69]

I doubt it's turbo as you'd hear it when revving in neutral.

Can't hear anything in video but from the symptoms I'd suggest it's transmission or drivetrain related.

 

[NeroRapid]

Sorry. By load I mean’t with drive/torque going through the gearbox as it doesn’t happen when in neutral.

how many km has the car done and has the gearbox oil ever been changed?

Right, sorry for misunderstanding It's only happen when accelerating on lower or higher speed. If revving on neutral is quiet. The current approx mileage now is more than 48,500 miles. Yeah, gearbox oil has been changed a few months ago in Audi Service.

 

[NeroRapid]

On attached soundtracks you can hear delicate whirling sound multiply times when accelerating so I hope it's nothing related to turbo but as you said when on neutral is quiet so it shouldn't be turbo.