I just changed ujoints in front and back prop shafts, now my 2004 Sportsman 700 started whining in high gear. It doesn't make any noise in reverse, Put it in high and as I pull away from a stop I get a pretty noticeable "rrrrrrrrrrrrrrrrrrrrr" whine that increases with vehicle speed. All oils are new and full. ??????

 

Could be either one of the two silent chains making noise,gear or bearing whine. Not worth tearing a gear case down for this.One of the few times I suggest trying an additive and I seen what this stuff can do as far as quieten bearing and gear whine.It's been out for many years and a lot of people seem to like it.May help quieten things down a bit. http://www.opmustang.com/store/p204/...ate_-_MGC.html I'd drain enough gear case oil so you can use the 6 ounce bottle of BG high pressure lube