I have a 04 (non s),with 41k miles, A very strange noise that appears to be comming from the front left ,( It is a noise very much like when you use to attach playing cards to your pedal bike spoke wheels ),a flutter type sound that increases with speed, in only happens whlie in gear, when you put the clutch in the noise stops , happens when moving in all gears, shifts fine, and the clutch doesn't slip... Any thoughts ?? some type of bearing problem ? Thxs

 

Bradey-- have a similar issue-- sounds like yours. I have an 04 MCS with 105K miles. I keep it tuned and in great shape, but noticed similar high pitch rattle/buzz when in gear, nothing when in neutral shifting or at lower speeds. Hard to identify where it comes from but sounds like left side. Thought about wheel but could not be since it happens only in gear. thought maybe exhaust system rattling when torque of engine vibrates chassis. friend owns tire shop and they looked underneath and found nothing (though they have no experience with Coopers). Dealership not close at all to me. Continue investigating. If I find out anything will share with you. please keep me posted in kind.

 

We took the car into the dealer.... they claim the tranny is on it's way out !! Going to a mini specailty shop next week for a second opioion .
Not good !!