My Legacy has 68,000 miles and just started making a whining noise from what sounds like the engine area only in reverse? 

Alan2012,

 

Since the engine turns only in one direction, whether driving forward or reverse, it cannot be the source of the issue.

 

Its either the transmission or half axle shafts, etc.

 

Your best course of action is to have a good mechanic listen to the car and diagnose the issue, if there is one. Its just too difficult for us to come up with a cause long distance.

 

Good Luck!