One week later, this noise is now very, very loud, even when I don't decelerate. As soon as I put the 5th gear and clutch, it vibrates whether I accelerate or not. It's like if the gearbox was going to explode.
I have a french car (Renault Scénic) with a manual gearbox (that's not the problem ;) ).
When I'm in 5th gear - and only 5th - and I remove my foot from the accelerator pedal, there is a continuous very loud noise, like if all the engine block was vibrating.
So, to reproduce the issue:
- 5th gear
- Any speed
- Foot off the accelerator
To make it end, I either:
- Accelerate (even if accelerate a very very little, the noise ends as soon as the engine drives the gearbox)
Can you guess where the noise comes from? Could it be the little metal bar under the card, linked to the gear lever that could vibrate against another part only when it's pushed far to the left (5th gear)? Could it be the gearing inside the gearbox?