I've upgraded from my tried and true Bayou 300 4x4 to a new 2012 Sportsman 500HO and I must say I am very happy with the machine and what it cost me. However, the new Polaris is a noisy beast. I've been told it was drive line noise due to lash between all the components but I 'think' it's getting worse. I've read all the posts about axle shaft issues and such but mine makes a 'clack clack clack' or rattle noise when off the throttle rolling down rocky trails. Not under acceleration and not while rolling down smoother trails. I jacked up the rear and rolled the rear wheels back and forth one at a time to check things out and I've worked on many ATVs over the years but this thing has one sloppy rear end. I only have 450 miles on it. I'm used to solid rear axles so are all these irs polaris' like this? Do the rear silent chain or chain tensioner gives problems?