2015 sportsman 850 won’t drive in any gear

Hi. I have searched and can find anything exactly like my problem. I have a 2015 sportsman 850 and this weekend while riding it got hard to shift. Eventually I was riding in low and it just stopped going. I took the belt box off and the belt is spinning, I can spin the drive shaft with my hands in every gear including park. I drained the transmission fluid and there were no chunks of metal and I can’t hear anything chattering that sounds like it Would be in the transmission. Anybody have an idea before I take it to the dealership?