03 Polaris 700 High Gear Issue

Just picked up an 03 Polaris 700 to replace the 04 I totaled a month ago. It rides decently and runs/idles right but it does not like to go into High gear, it grinds and won’t engage most of the time, sometimes will engage if you get it moving in in low then push it into high, and sometimes will engage if you push the shifter forward hard, and sometimes it works fine. I’m going to be tearing into it this weekend and need some ideas where to start. Has 446 hours and 2314 miles, don’t know the age of the belt. Any help you guys can give me is much appreciated, hope its not about to blow up on me lol