I have an old Permagreen Centri that I use a few times a year. Last summer, it started making a high pitched squeel while moving. It wasn't a belt issue and now (after sitting a few months) it will not shift gears from forward /neutral/revearse. I think I locked the transmission up and unfortunately I just put a new Honda engine on it last year. Anybody had this happen? and does anyone know if you can replace the transmission? I'm not sure this old thing is worth the work or money, but wanted to find out. Thanks for any input.