Purchased by The Toro Company from American Motors Corporation in 1986, Wheel Horse brand tractors are known for having a simple and reliable design. Engineered for longevity and low maintenance, Wheel Horse tractor transmissions are a manually operated single-ratio gear-box system that changes the speed, torque and directional output of the engine. Rebuilding a Toro Wheel Horse transmission is a straightforward procedure easily accomplished by most weekend mechanics in a single afternoon.
Things You'll Need
- Long screwdriver
- Rubber mallet
- Clean cloths
- Masking tape
- Felt-tipped marking pen
- Replacements gears and shafts
- 1/8-inch drill bit
- Small flat-head screwdriver
- Bearing grease
- Replacement bearings
- Replacement bearing races
- Socket wrench set
- New transmission casing gaskets
- Torque wrench
Place the transmission in low gear. Insert the shaft of a long screwdriver through the center of the U-shaped joint connecting the transmission to the driveshaft; remove the pinion nut from the driveshaft with a wrench.
Disconnect the transmission from the engine flywheel, the transmission housing from the engine block and the transmission from the transmission mount with the appropriate wrenches.
Set the transmission on a workbench. Remove the bolts connecting the cover at the front of the transmission with a wrench. Tap the cover with a rubber mallet until the cover comes loose from the transmission casing.
Wipe the grease from the ends of the gears and shafts with a cloth. Attach a piece of masking tape to each shaft and gear and write a number on each piece of tape with a felt-tipped pen. Draw a diagram, on a piece of paper, with the marking pen, referencing the position of each gear and shaft with the corresponding numbers written on the masking tape.
Remove the bolts connecting the transmission case sections with a wrench and separate the case sections with the rubber mallet. Work the gears and shafts free from the transmission casing with your hands.
Clean all surfaces of all gears, shafts and transmission casing sections with a clean, lint-free cloth. Thoroughly examine all moving parts for signs of wear. Obtain replacements for any worn parts, specific to your tractor, at a tractor supply store or online.
Drill a vertical hole, with a 1/8-inch drill bit, down through the side of the shaft bearing races on the inside of the transmission casing. Gently hammer an awl into the drilled hole until the race snaps off. Carefully work the race from the bearing socket with the tip of a small flat-head screwdriver and then remove the bearings with the screwdriver. Wipe the bearing sockets clean with a cloth.
Work fresh bearing grease into new shaft bearings with your fingers. Set the new bearings, with the domed side of the bearing facing the inside of the transmission, into the bearing shaft sockets with your fingers. Set a new bearing race over the bearings. Select a socket, from a socket wrench set, with the same outside diameter as the bearing race. Place the socket over the top of the races and tap the races into the holes with a hammer until the top of the races are flush with the inside surface of the transmission casing.
Install new gaskets on the transmission case sections and resemble the casing with the wrench. Remove the masking tape from the shaft and gears one at a time. Coat the shafts and gears thoroughly with bearing grease and reinstall the parts into the transmission, referring to the numbers and diagram as needed. Bolt the cover to end of the transmission with the wrench.
Reinstall the transmission on the tractor; reconnect the transmission to the transmission mount, driveshaft, engine flywheel and engine casing with a torque wrench set to 18 foot-pounds of torque.
- Tractor Data: Wheel Horse Lawn Tractors by Model
- Yard and Garden Tractor Service Manual; Primedia Business Media
- Garden Tractors: Deere, Cub Cadet, Wheel Horse and All the Rest, 1930s to Current; Oscar Will
- Photo Credit Comstock/Comstock/Getty Images