I drained the rear differential. The Honda Dealership here in VA decided they didn't need to change the rear diff. oil for some reason b/c it was nasty grey. For anyone concerned, I used Valvoline Synthetic Blend 80w90. Turns out that my noise is coming from my left rear wheel bearing. I jacked my car up, grabbed the tire & shook, and there was probably 3/16" free play. I know everyone likes Legacy bearings but I'm going with the ones from Advance with a limited lifetime warranty for $73.
-Charles-