Transmission and Transaxle Troubleshooting

In the following information, I am assuming that you have a good, properly adjusted drive belt and the keys are in the axle that hold the wheels on.

Problems with Gear Drive Transmissions

Shift keys are worn. The keys loose their “spring” and allow the mating gear to slip around it, causing the jumping condition.

Input and Output shaft bushings are worn. Replace with new ones.
Rust on the input shaft. Caused by moisture in the case. Disassemble transmission and clean, replace any hard grease.
Shift detent balls over adjusted. The one or two set screws next the the shift lever control the pressure on the detent balls. Back the screw off and reset them so the screws are just a little snug when you tighten them down.

Teeth are clened off of input/output gears. This happens when you “dump the clutch” when taking off. Also, changing gears without completely clutching will damage the gears.

Input shaft and/or bearings are worn. The input pinion is not properly aligned with the mating bevel gear, causing the input motion not to be transferred to the other gears. Caused by normal wear or excessive tension on the belt.

Brake is out of adjustment. Some MTD transaxles use a castle nut and a cotter pin to keep the nut from coming off. Remove this pin before adjusting. With a half inch combination wrench, reach under the right side (most tractors) and tighten the nut until you cannot push the tractor. Now back that nut off until there is slight resistence when pushing the tractor. If this does not fix the problem, see below.
Brake pins are stuck. Remove the nut and loosen the right bolt that holds the brake assembly to the transmission. Remove the metal retaing piece and the brake lever. Now remove the other bolt and remove the pad housing. Remove the brake pad and the metal protector. If the pins are stuck, use a pin punch to remove them. Now with pliers, clean up the pins by using a wire wheel on your bench grinder or you can use a hand wire brush. Clean the housing with carburetor cleaner and apply Never Seeze to the pins. Re assemble in reverse order and adjust the brakes.
Grease on Pads or Disc. Follow directions above to remove the brake pads and replace them. Remove the brake disc to replace the pad behind that. Clean up any grease leaking from the case. Clean the brake disc with a good carburetor cleaner.
Broken brake disc. I have seen this happen on Foote transmissions with an internal brake disc. The transmission must be taken apart to fix.