The mower starts and the engine runs fine, however, the tractor won't move; there is a freewheel/engage lever on the transmission that seems to do nothing as the tractor will only freewheel.
Have you removed a rear wheel at some time? if so you may have lost the square drive key between axle and wheel, if not it is possible the bypass lever is being held up for some reason, clean all grass debris from around the lever on the gearbox
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