The Sonnax high clutch drum thrust washer 28406C is designed especially for the extreme loads seen in race-only applications. The tri-metal thrust washer is made of lead-bronze on a steel backing, then lead-tin plated to withstand the highloads of drag racing. The washer is also designed with four oil grooves to increase surface lubrication for longer service life. At .078" thick, it can be shimmed for precise clearance.