Cluster Gear Rear Thrust Washer (Slot-Style) 1940-1953 This is the thick metal thrust washer that fits on the rear of the cluster gear in between the gear and the transmission case. This thrust washer fits 1936-48 cluster gears (which have all helical gears) that have two tabs that protrude outward on the rear of the gear. This washer is included when you buy the (A0A-7130) thrust washer kit. If your cluster gear has 4 slots on the rear of the gear you will need the rear thrust washer which uses part number (68-7129-B), which has four tabs that protrude out from the thrust washer.