I received a call from my Service manager today. They believe that the problem stems from a faulty computer part that supports the windshield wipers. Still something of an exploratory expedition, the Service Manager said, "we think we're in the right area." Not terribly reassuring.
The theory is that there is a computer that controls the rear window wiper and it wouldn't turn off. In addition to the noise, the display showed that the windshield wiper fluid was low when in fact it wasn't and so these two issues are related. They are getting the part shipped to them and they'll have my x3 until Monday.
Colors: Vermillion Red and Sand Beige Leather, Fineline wave wood trim. Y Spoke wheels. Nice! Convenience, Cold Weather Pkge I & II, Premium Pkge and Rear View Camera. And I really like that they used dark carpet in the cargo area. Smart!