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Last night backing into my driveway after work I noticed a strange vibration in reverse. After noticing it it seems it does it if only slightly in P/D as well, so little you're not sure but you think you feel it... but greatly more so/magnified in reverse.

It feels/sound almost like the engine/trans are touching the body somewhere. The cabin resonates with the vibration. I thought it possible perhaps I'd torn and collapsed an engine mount or the like.

Tossed it up on the lift at work today and verified there is nothing touching anywhere, all mounts look great, but it seems like the noise/vibration is coming from the back end of the transmission.

The vibration is engine speed dependent, and rises in frequency until it goes away above 1k or so. No odd noises otherwise, and it only makes it at idle speeds. Up over 1k or so the noise is gone regardless of gear selected.

[hawkjr1]

My 2013 535i M Sport is making some strange whistling/whining sound when backing up. I didn’t notice any vibration at least not yet. It has been in the shop for two weeks for that noise I was hearing. They called me today and said the noise is normal. I had another 2013 535i before this one and it didn’t make that noise. Wondering if you had any weird sound when backing up.

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I'm pretty sure what I'm dealing with is just an unfortunate exhaust resonance that is exciting *just right* to be annoying as hell. It only makes it at idle or below, raise it just 50rpm and it goes away.

Having someone under the car on the rack grab the exhaust to deaden the vibration reduces the noise/feel in the cabin hugely.

The rubber dampers on the exhaust piping are doing work, but there is a resonance outside the hertz they are tuned for.

I think it started doing it following the Pure Stage 2 turbo installation and I just didn't notice right away as I don't always back into my driveway. Stands to reason the exhaust flow changes would also effect resonant harmonics, just a question of how to quash them.