This authentic OEM item is specially made for MTD and Troy-Bilt tillers. It is one of the special seals for the transmission shaft. Unfortunately, over time the material tends to wear out and it may begin to crack eventually requiring a replacement. Keep in mind this high-quality oil seal is made of durable rubber and is sold individually...Read more. Check the owner's manual and the diagrams for your model to ensure the correct repair procedure. A wrench set will be needed to replace this component.