A flywheel is a large rotating mass mounted on the rear of the crankshaft.
On a car with manual transmission, the flywheel is very heavy, and its momentum helps smooth out engine operation.
The flywheel links the crankshaft to the transmission, through the clutch. The flywheel has a machined rear surface. It is the clutch’s main driving member. Holes are drilled and tapped into the flywheel for attaching the clutch pressure plate.
On a car with automatic transmission, the flywheel is usually called a drive or flex plate. The drive plate is lighter than a conventional flywheel because of the weight provided by the torque converter.
The outer edge of the flywheel or drive plate has a gear called a ring gear. The electric starter pinion engages on this gear to rotate the engine for starting.
