Ever since my 100k service, I have been getting what I think is the drivetrain whine that so many have experienced. It happens when I'm on the gas between 53-59mph and gets louder the more throttle you give. The pitch doesn't fluctuate with RPM so I'm 95% sure it has to do with driveline. BTW - there is no adverse affect on performance other than the noise. I took out my entire front driveline (diff, axles, front driveshaft) and have been driving around the last few days. The driveline noise is gone. So now I am staring at my M205 on the floor of my garage, wondering what I should do next. Is it worth opening up and looking into? Can this noise be caused by not having enough fluid? Even if I open it up and find a problem, can I even do anything about it short of rebuilding the whole diff? Seems to be to just let it go until it really becomes a problem. I've heard people have driven 80k miles with whine... What do you guys think?