It sounds like you have a final drive carrier bearing that is out in the transmission. This is not too common but it does happen. Raise the car front on jack stands and run it at 35 MPH then you see see where the noise is coming from the confirm the failure. You can also put your hand on the case to feel the vibration.
If so the transmission will need to be rebuilt FYI here is how it is removed. Here are diagram to help you remove the unit.
Check out the diagrams (below). Please let us know what you find.
Images (Click to enlarge)
Sunday, November 7th, 2010 AT 12:48 AM