High pitched whine after DCT 1200 mile service
I Just had the 1200 mile service, and now my 2011 e90 M3 has an annoying high pitched whine when accelerating, starts at about 1500 rpms, increases until it (or I) shift(s), depending upon the mode, then continues through each gear. DCT transmission, happens in auto or "manual," with power button on or off, in m mode or not, and while revving in neutral. It didn't do this for first 1200 miles, and I can't think that changing the oil, oil filter or differential fluid would cause this. It's more noticeable inside the car than outside. It's not the air conditioner or the audio system. Really annoying. Any ideas? Belt?