Sounds like a square taper crank. Riding with it loose just makes it worse. Its actually the crank that is shot, wear on the inside of the crank makes it loose. Usually caused by a loose bolt allowing the crank to move. 'Ya need a new crank. Note as well, the square taper shaft is steel, the crank is aluminum. Crank loses in those situations.
Last edited by Steve B.; 11-19-22 at 09:46 AM.