Rubber Insulator for Propshaft Bearing - Mitsubishi Lancer 1.8 Turbo GSR CM5A These are a steel washer with a rubber surround, the rubber can perish and allow movement of the propshaft bearing. This can cause shaking/vibration and a wump wump wump sound. Eight of these are used, Four on each propshaft bearing. See HERE Mitsubishi Part Number MB837586