Small Engines (Lawn Mowers, etc.): Toro transmission, drive gears, jim caldwell

Question
I have a 22" Toro walk behind lawn mower model number 20017, serial number 240000001. This past weekend the transmission for the rear wheels started making a loud clicking noise when engaged and when I needed to back up the wheels tended to lock up. The mower is about 4 years old. Any help would be appreciated. Thank you very much.
Jim Caldwell

Answer
You need to remove the rear wheels and see what is going on, you will
likely find the little drive gears are just rusty or gunked up,
and disassembly, cleaning and lubing is all you need to do.
  Remove the little gears, noting which way they turn as they can be reinstalled backward, and clean and lube, look at the keys, if they are worn badly, should be replaced.

Google "Milaca Lawn and Garden" for a free parts blowup.