Tranny whine

[dep156]

I have a 1999 Fatboy with a six speed installed. The person that I bought it from installed it, so I don't even know who the maker is, I assume it is a gear set that was installed into the stock tranny box. My problem is that it whines in 3rd, 4th, and 6th gears. I understand that some of the tolerances may be off, but instead of taking the tranny apart, I would like to know if there is a tranny fluid out there that would at least quiet it down a little. Thanks

[Faast Ed]

Redline Shockproof has been knownd to quiet a few down.