How to Replace a Transmission Belt on a Lawn Tractor

The transmission belt of any lawn tractor is what keeps it moving forwards. This is obviously an essential function of a lawn tractor. But over time, a transmission belt can become worn out, torn, or even snap. Thankfully, replacing a transmission belt on a lawn tractor can be done fairly easily at home.

Man mowing lawn
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How to Replace a Transmission Belt on a Lawn Tractor

What Is A Lawn Tractor Transmission Belt?

A lawn tractor transmission belt basically works to transfer power between the different parts of a lawn tractor. Typically, the transmission belt transfers the power from the radial torque of the engine shaft to the input shaft of the transmission. When the input shaft is powered, it turns, performing the two main functions of the lawn tractor. These are the forwards motion of the motor, and the spinning of the blade. Essentially, the transmission belt powers the motion of the lawn tractor.

How Will You Know When Your Lawn Tractor Transmission Belt Needs Replacing?

The most obvious clue that your lawn tractor transmission belt has broken is if the lawn tractor stops moving forward. This will likely mean the transmission belt has snapped. However, for safety reasons, it's generally a good idea not to get to this stage. So before mowing, you can easily check your transmission belt for any tears or frays. If it looks worn out, it's time to replace it.

How Do You Replace A Lawn Tractor Transmission Belt?

Firstly, you'll want to make sure the tractor is parked on a level service, and that the engine doesn't have any power. Disconnect the spark plus wire in order to be safe whilst replacing your transmission belt.

Then set the deck-height lever on the tractor to the lowest setting.

From the left side of the mower deck, open the idler pulley using a 15 millimeter wrench. Pushing the wrench forward will take the pressure off the transmission belt. Remove the spring attaching this pulley to the transmission belt. You should then be able to slip the transmission belt off of the idler pulley and transmission pulley. This is best done in a rolling motion.

Next, place your new transmission belt over the two pulleys. Re-attach the spring to bring tension back to the transmission belt. Release your wrench from the idler pulley.

You can now reconnect the spark plug to the spark plus wire. Turn on your lawn tractor in order to test to see if the new transmission belt is working properly.