After a month of driving around with sounds of my AW70 tapping and grinding, I've finally located the source of the problem. It was not in the tranny as I had thought but a broken right motor mount bolt......... The broken bolt caused the engine to sit a little lower and misalign the engine with the tranny just enough to make noise but not impair drivability. I noticed this when I was changing the oil and the motor mount was pressed up against the filter making it impossible to unscrew it. I ended up putting the front up on jack stands and jacking the engine up high enough to remove the filter - I'll have to get back to the motor mount this weekend.

If any one has any suggestions on changing the motor mount I'd appreciate it!