while doing a speed trial with the walking machine, I heard a loud crack/snap sound. The machine stopped in its tracks so I shutdown the engine. There was a large crack in the cases of the transaxle. Looks like the transaxle is toast. I have another transaxle but its larger and would take quite a bit to fit it into the machine. I may change to a straight axle with several jackshafts to gear it down for a single speed, no reverse machine.