Team Associated RC10B74.2 Factory Team Machined Rear Gearbox Pinion Height Inserts. This is an optional part intended for the RC10B74.2 and B74.2D series of vehicles. These aluminum pinion height inserts allow you to adjust the pinion height for proper gear mesh when adjusting the differential height. Package includes one 0-3mm pinion insert and one 1-2mm pinion insert.