I have a '99 Softail custom 80ci. I read on this site from multiple posts that people are running mobile 1 75w-90 synthetic gear oil in their trannys so I decided to give it a try. They were all right about how smooth it shifts, but now I'm hearing a noise that sounds like a bad bearing coming from the tranny. It doesn't do it at idle, only when I rev it up. Any ideas as to what I'm hearing and why?