A John Deere SX-85 driving a lawnmower equipped with a Peerless 910 series transferable is great equipment but it could create a problem if you do not read the john deere technical manuals pdf carefully. The problem arose after mowed grass twice since fitting all new belts over the winter and during the second cut, it stops moving upside down. Even after you have used reverse on mowers many times and know about the safety mechanisms needed to reverse, security mechanisms below because they could fail and cause problems, despite doubts. It won’t be reversed. Even with the engine off, the mower disconnected, and in neutral, you couldn’t even manually pull it back.
Engine stop when the shifting lever is moved to the R (REVERSE) position and the Attachment Engages in Normal condition. (See Using Reverse Implement Options in OPERATIONS section.) It seems that the gear selection lever will not even move to the “reverse” position. The lever moves to the “reverse” position, although it has the same “feel”. Pressing the gas in “backward” doesn’t move the tractor, only strains the engine. The left wheel turns forward and the right wheel turns backward. So if you take the left side of the lawnmower, you can make it move backward. It’s a struggle, but you can move it.
This sounds as if something internal to the transaxle is toast. The differential itself works, as evidenced by your ability to move forward and be able to rotate the tire in the opposite direction (this indicates an “open” differential). You put it on the lever with the lever, which is evident from straining the engine while pressing on the gas. It is suggested that you have to do some internal transaxle work to fix it. There must be an intermediate gear that changes the direction of work rotation which may be wrong. Do you ever know what the problem is? Not because you have the same problem, but because it would be nice to have this resolution for someone else with the same problem. So make sure to get the manuals to help you fix the problem.