Manual Transmission Flywheels & Components

A smooth flat surface is crucial on transmission flywheels to provide the best clutch operation and grip. Worn and uneven surfaces cause vibration and chatter when engaging the clutch, which leads to possible clutch disc slippage and an undesirable driving experience. Though resurfacing the flywheel is an option (as long as it meets minimum thickness specifications), purchasing a new flywheel provides a quicker solution and an opportunity to upgrade from the current version in your vehicle.

There is nothing worse to hear when you are turning the ignition key than the screeching and grinding sound of the starter gear attempting to engage worn flywheel ring gear teeth. Replacing the flywheel will resolve this issue. In addition, prevent other possible starting noise by checking the starter drive gear to make sure its teeth are not also damaged. It is also important to confirm the starter is properly aligned with shims to make correct contact with the flywheel ring gear.

Flywheels in cars, trucks, race vehicles and other automotive applications provide a friction surface for the clutch disc. They also incorporate ring gear teeth around their perimeter to allow the starter to crank the engine in manual transmission applications. Flywheels are bolted to the rear flange of the engine crankshaft. The clutch pressure plate then bolts to the flywheel with the clutch disc in between, supported and aligned by the transmission input shaft. The clutch release / throw-out bearing (which is actuated through a linkage, cable, or hydraulic operation from the clutch pedal) controls when the disc grabs the flywheel to transfer power from the engine to the transmission.

Depending on the engine / transmission application and flywheel dimensions, replacement costs can range in price from $75 to over $900.

Manual and automatic transmission flywheels are not the same. Though similar looking, an automatic transmission uses a flexplate instead of a flywheel. A flexplate is a thin disc-shaped component with a ring gear around the perimeter. The flexplate bolts to the engine crankshaft in the middle (like a flywheel) and the torque converter towards the outer perimeter. A manual transmission flywheel is thicker and heavier than an automatic flexplate for heat dissipation and strength as the clutch disc grabs it in order for power to be transferred from the engine to the transmission. The flywheel also has threaded bolt holes for the pressure plate to bolt to it.

There are certain conditions that can contribute to gearbox damage caused by a manual transmission flywheel. If the flywheel is not true / straight or is incorrectly balanced, the manual transmission input shaft could have extra pressure or vibration put on it, causing bearing or seal damage in addition to other components. A vehicle accident or flywheel failure (such as ring gear separation or poor build quality) could cause the flywheel to contact and damage the gearbox and its components as well.

If you are experiencing grinding or screeching noises when starting your engine, vibration and clutch chatter when shifting, or working on a new build and don't have a flywheel, JEGS can help. Shop our wide selection of flywheels for sale as well as related flywheel components, which will help provide noise-free starting and smoother clutch engagement.