2005 Nissan Altima, auto transmission We are getting a weird sound from the engine compartment area. It could be coming from the tranny/drive train....but don't think it has anything to do with the engine. Here's the deal.... The vibration & sound starts at about 30mph and seems the loudest at about 40-45mph. This sound is apparent when driving down the street. When the vehicle is in park or neutral and we rev it completely through the RPM range....no sound when still. One test we did...we rolled the car up to 45 mph...and let it coast in neutral and the sound is present, then disappears at about 30 mph. This sound has appeared about 6 months ago and we have been driving the car on a daily basis. We mounted and balance new tires and did a new alignment....which did not eliminate the sound/vibration. Can anyone help?????