When Im driving around 30 to 45 mph my car sounds almost like a helicopter. I also noticed that when I park the car and put in first and slightly let up of the clutch (riding it ) I get a similar helicopter sound. I don't feel it in the stering wheel while driving. I think its the axle. I did a complet suspention inspection and noticed my rear trailing arm bushings are shot. What bad thigs could come of those bushings looking like hamburger.

 

my car sounded like a helicopter when my wheel bearings where shot, not sure if that helps u.