Any legal binding after sale of car?

No there was nothing signed… He called about the car, I told him what I think is wrong with it. Offered to let him fix it in my garage. He paid me, transferred the title and he was on his way. I didn’t hear anything until last week when he said the heater core was acting up. Now he tells me that the tranny is shot. I offered to point him in the right direction, but I’m not buying the car back.