its for sure not a whirring sound.. and i hate to say grinding, because its not a hard "bad shift" kind of grind.. more like the sound the brakes make when you have no pads left, that kind of metal on metal sound.. but its coming from the tranny.

 

Kinda like a subtle, continuous "coughing up phlegm" type of sound - like you are saying the phoneme "ch", but down in your throat?

 

Did you test drive it before you bought it in the first place? A good thorough test drive with the radio off and the salesman gagged goes a long way to identifying issues before you deal on a car.

Mike