The whistling sound that stops when you press the button

Hello, I have a Peugeot 207. When I step on the gas pedal while idling or driving, I hear a whistling sound, as seen in the video. This sound stops when I press the clutch. When I took it to the mechanic, he told me that the transmission needed to be disassembled. I just changed the transmission fluid. I didn't hear this noise before the change. What do you think could be the cause? https://www.youtube.com/watch?v=fmEredg3lRU&ab_channel=AliEri%C5%9F erisalican2023-06-11 22:24:44

The sound originating from the clutch release bearing makes a whistling sound at first, then turns into a whirring sound when it breaks down completely.

I changed the pressure plate and the pressure plate bearing based on what I read on forums and the mechanic's advice, but the noise still persists. The mechanic couldn't understand it and said, "No problem, just use it." I'm starting to get really fed up with the car; there's no part left that can't be replaced.

I have the same problem and it still persists. Even if you change the pressure pads, the noise persists. My mechanic said it is because the transmission is old and it is not a problem.