Vehicles with manual transmissions have a flywheel. The Flywheel is where the clutch assembly is mounted. It provides a smooth friction surface for the clutch disk. Flywheels also have teeth for the starter.
installed new clutch and flywheel, on start up engine shook so bad i had to shut it down. i inspected each part , the flywheel was extremely out of balance, was necessary to replace flywheel with another brand.