[Andrius]

I have a 318D N47.

I notice a "rougher than usual" sound coming from my engine.

If I put the car in N, the usual diesel noise. But when I put it in R or D while still holding the brake and the car not yet moving, the engine sound gets rougher. If I put it back to N, the noise back to normal.

The RPM is not fluctuating at all. Just the noise. And the car itself still working.

The gearbox shifts smoothly, there are no vibrations.

Do you have any advice or can you imagine where the problem might be?