Finally got my new LE 570 out for a good ride in the mountains. Love the machine other than the loud rearend. This is my 3rd Can am (had 11 commander that I traded for a 15) and the rear diff sounds way worse than my 11 commander. The 15 Commander is much more quiet. Anything above 20 and it hums and whines like crazy. Is this normal? Any help would really be appreciated.