Just picked up a Boxer from an auction which claimed it to be running and driving - it does, just super slow. The machine moves and the hydraulics work - just at a snail's pace. It shifts between the two speeds but unless the machine is revved up to the max in high gear, it barely moves. Hydraulic fluid is full and I changed the filter but no change. Cant find a service manual for any Boxers other than an operator's manual - any help or ideas would be most welcome. Thanks!