A week ago, my 2012 mini cooper S all of sudden developed wa wa wa rotational sound while driving.
The sound is not speed dependent, noise is still there in 10mph and 60mph. Just frequency gets faster. I can feel a bit of vibration on the gas pedal too.
Upon inspection, noticed axle shaft seal was leaking, which will cause low on transmission fluid.
Questions.
1. based on photos, can you confirm if it is shaft seal leak?
2. can low transmission fluid cause wa wa wa rotational sound?
3. Also, do you know what is the black (red arrow) plastic piece is where axle meets transmission? Is this some kind of dust cover? Is this part of axle?

 

It sure looks like a transmission driveshaft seal leak. Better check you fluid level asap.

How many miles on the car? If you're over 100K, it probably the wheel bearings making the noise.

Yes I believe the black ring is part of the driveshaft assembly.

It is possible to pull the driveshaft and replace the seal.

See items 11 & 12.

https://www.realoem.com/bmw/enUS/sho...diagId=24_1063

 

The hard plastic ring on the axle shaft is just a dust cover of sorts, the seal is on the housing

 

Thanks guys.
Yeah. I need to check the fluid level, but since it's due for transmission fluid change, I'll do it at that time, together with replacing the seal. New seal is ordered already.
As for the wa wa wa sound, there was a huge nail in the tire. Patched and it's all good now.