I have John Deere SX-85 riding lawnmower which comes with a Peerless 910 series transaxle. It has mowed the lawn twice since the installation of all new belts over the winter. During the second mow, it stopped moving in reverse.
We have used the reverse on the mower numerous times and know about the safety mechanisms required in order to reverse. i listed Hyperlinks to the safety mechanisms below because they could be failing and causing the problem, albeit doubtful.
It will not go in reverse. Even with engine off, mower blades disengaged, and in neutral, i cannot even pull it backwards manually. I can push forwards however and the lawnmower still mows grass in forward direction. I will have to pick up the 367 pound lawn mower to get it out of the garage!