[Tony Silva]

Grinding only going into reverse leads me to believe that the syncro's for reverse are bad and that would mean it's a time for a rebuild. Or you could just live with the problem till the tranny finally breaks. I had a 2000 Cougar (same car as the Eclipse) and it did the same thing. Drove it for about 2 years with the grinding happening till the tranny finally broke.

As for the sound coming fron the front left of the car when the car is in gear...you didn't mention if the car is in gear AND stationary or if the car is in gear AND moving......so which is it?