Clint’s John Deere Spoker D (left) features an engine and transmission from a combine, an idea he borrowed in part from another hobbyist. His Deere-related Dain (right), like the original, has no differential. The full-size tractor used self-reversing ratchets on the front drive sprockets. To go in reverse, the rear wheel would roll back enough to trip the ratchets. “I couldn’t duplicate that, so I used a transaxle,” Clint says.