Just finished up ridding 30 miles today and my buddy told me that my Polaris is making a weird noise coming from the back end of the atv. I also can notice the noise at around 15 mph or greater and it’s not the tires but it’s a humming noise. Is this normal on the 1000XP? I have 220 miles on it and 18 hours so far. The only thing I can guess is the rear differential. Any advice or suggestions greatly appreciated.