My 1999 Sportsman 500 started making a high pitched sound coming from the transmission. It's really loud when you accelerate and quiets down some when costing to a stop. Upon investigation I noticed A LOT of water in the transmission fluid (real milky). Upon further investigation, I found the air vent hose on the top of the transmission was off, allowing water to enter the transmission when riding in water. I changed the fluid about five times but the sound is still there, no better at all. Have I possibly damages the bearings. Any ideas???