I was told that it is comon for the can am rear end to wine .When I had my can am atv's my wifes had a lot of noise were my atv that was the same size ,year and everything didnt have the noise. Mine also seemed to be faster and loser like in a higher gear or something.It wasnt were eather one of them went because where her machine was rode mine went rode also. now with the camander it has the noise also I hoped it would have been like my atv but its not. The dealer here says it is the belt and thats how it is. nice hu?BRP replaced my rear diff a couple of weeks ago, well I mean they gave me the diff & I had to install it. But I'm fine with that. I've had my X since Oct 2010 and warranty ran out Oct 2011. I think it's mostly how good your dealer is as well, I talked to my dealer a couple of times in the past about how loud it was at fast speeds but they thought it was normal since basically they all are like that. Anyways, brp gave me a #506 this time instead of the #411 - Just cruising through the neighborhood it still sounds loud but don't know for sure until I get it out in a couple of weeks.
Glad to hear the new diff is quieter .....is it a 411 or 506?...hope it continues to be in hush mode for everyone that gets a replacement ...so as the hundreds of miles gets put on yours, try to notice a difference in the howling of it and keep us posted pleaseJust wanted to update post. I got the new diff installes yesterday an went for a quick drive 100% improvement much quieter now. I am very impressed with brp for taking care of this problem without any drama.