08 Polaris speedometer problems

Hi, I'm new on here. I was out on my 2008 Polaris IQ LX 750 turbo today for the 1st time this year, and it ran great. Only issue I was having with it was the speedometer was out of wack. When the sled was stopped, both my digital and analog speedometers were bouncing around like crazy, it was saying 20mph then it would jump up to 80mph, and the sled wasn't even moving, it does it both when the sled is idling and when it is not running but the idiot lights are on. I wouldn't have paid much attention to it but the sled won't go into reverse unless the speedometer says 0. So now I don't have reverse. I talked to a buddy of mine who has a 2015 assault and he told me his speedometer started acting up last year, and he kept riding it, but he ended up screwing up the barring on the drive shaft and ended up with a $800 repair cost. I'm wondering if anyone else has had anything like this happen? And what the cause was and the best way to go about getting it straightened out? Thanks, Jake

08 Polaris speedometer problems