Messed with the car a little more today. Have a recording but can't upload. May have to do the YouTube thing. Anyway I get the sound in all 3 forward gears so I guess it's not the low gear set as moparlvr166 pointed out. It's an odd sound almost like a generator winding down as I coast and slow down. Kind of like Grrrrrrrrrrrrrrrr. Not a whine.
So, you only hear the noise on deceleration, how about normal accel and hard accel then steady speed at 60MPH? then tell us what you hear when driving steady 60MPH and lightly accel an decel up and down? Drive again and let us know when it happens.