Twin Mass Flywheel

Most service professionals consider the dual (twin) mass flywheel to be a wear item, and recommend replacing it as part of each clutch job. Resurfacing of dual mass flywheels, common with conventional flywheels, is impractical and not recommended by many OEM's, including BMW and Porsche. In fact, reusing an old dual mass flywheel with a new clutch friction disc often results in unwanted noise, vibration, and harshness, due to torsion spring wear.

ECS recommends installing a new dual mass flywheel when replacing the clutch friction disc.

How it works: Dual (or twin) mass flywheels are made of two separate flywheel discs separated by a friction ring, and coupled through torsion dampers; springs or planetary gear sets. Transmitting drive from the engine to the transmission through vibration dampers isolates crankshaft torsion spikes, reducing transmission gear rattle, gear selection effort, and synchronizer wear. Failed dual mass isolation springs and gears cause noise and vibration.