I need some help I was driving my 3 wheeler yesterday and pulled up to a stop sign and heard a loud clunking from motor and i continued to drive like nothing ever happened...

I got home and was gearing down to neutral while stopped, the clunking began again and stalled the trike now it seems seized but i can turn it over but doesnt feel like it turning the motor over just feel rubbing, doesnt feel good anyways i have got the rear end off thinking it was an issue there but has done nothing and everything looks fine just looking for any ideas before i go any further thank you!