One of the guys on www.polarisatvforums.com thought somebody here might be able to help me. The roll pin on the rear yoke dug a hole in my transmission and filled it with muddy water. I didn't even realize it 'til it started whining. Well I repaired the case and replaced every single bearing in it, but there's still some whining in high. Kind of like the whine from a worn out rear end. My assumption is the muddy water caused the main gears to wear excessively, even though they look fine to the naked eye. I'm looking for a deal on a used tranny or better yet just the main gears. Maybe somebody has one with a damaged case they want to part out? If somebody has something or knows where I might find some good used parts please let me know. I'm using it, but the whine is a little annoying.

 

If you replaced all the gear case bearings and seals, I'd be more suspect of the ring and pinon gear(#46,#49) that could be causing the whining or possibly the silent chains if you didn't replace them when you replaced the bearings. But again there's a lot of parts in this transmission and it could be anything if filled with mud.Dirt Cheap Yamaha & Polaris OEM Parts & Accessories – Cycle Parts Warehouse

 

Yep, I replaced all the ball bearings, as well as the needle bearings on the mainshaft. All the seals and shift gear cover as well. Normally I would agree with you on the ring and pinion, but there is no whining in low or reverse. Even if I put it in low and try to increase the load by holding the brakes. Only high gear whines which causes me to think it's that first gear on the input shaft and the corresponding gear below it. Those are the gears under load only when in high. The noise also seems to be coming from higher in the case than the ring and pinion. I was kind of surprised Polaris uses straight cut gears. Helical gears are much quieter, but probably more costly to produce. It would be nice to find one with a cracked case, but otherwise good internals.