96 Jetta transmission whistle?
 

I have a 96 Jetta GLS 2.0, automatic transmission, and I have noticed a sort of whistle that only seems to happen in 2nd gear and @ about 3000 RPM. It also seems to happen most when coming out of a turn when I get back on the gas. If I ease through the gears, I don't hear it. The whistle is also accompanied by a very slight rumble.

Any ideas?