[Hordec]

When driving in sports mode and the car sits at around 2100 + rpm (easier to notice at lower speeds and gear) it makes a humming / brrrr noise before changing gear, after the shift the noise disappears. It only makes the noise at these revs and not when lower or earlier shifts in comfort mode. Any suggestions? (16' M135i Auto 36,000 miles)

 

[Dale1uk]

Possible loose exhaust heatshield?

 

[Hordec]

Possible loose exhaust heatshield?

It sounds too mechanical and uniform to be that, almost like an unbalanced prop shaft for example as the sound comes back each time at the same criteria...but if it was that, why does it only occur at 2k+ and not lower, or even get worse..