I have an old (about 30 yrs) Toro 724 with 3 speeds fwd & 2 rev. The engine runs fine and it was working great during our last big snowstorm, but now the transmission seems to be locked up after 4 hours of heavy use. If I put it in neutral with the engine off and drag it backwards, it makes a clicking sound. It won't go into any gears without a lot of coaxing. I inherited this thing and don't even know if it uses transmission fluid. Don't know if it is still worth fixing.