I have a 2003 C320 with 700 miles. I tried the touch shift for the first time today. When the RPM dropped down to about 2000 RPM after taking my foot off the gas pedal, I heard a whine which persisted for another 200 RPM. It happened in first, second and third (I didn't try fourth or fifth). I drove the car with the service manager who said it was "the gears meshing." Has anyone else heard this noise?