what might cause a buzzing sound that increases with rpms only in drive?

What is your question?

The sound only occurs in drive, nothing in park, or reverse, reving or at idle. I was told at a GM dealership that a bearing was going out in the trans. and they could replace it with a rebuilt for $3,500. I don't think that putting that much in a eight year old view is worth it. Could this be caused by anything else?