The Eaton Fuller Countershaft, part number 228580, is a genuine Eaton Fuller transmission component sold by Pro Gear and Transmission. The countershaft is a critical internal gear train component in Fuller heavy-duty manual transmissions, transferring power between the input and output shafts through the mainshaft cluster. If you are sourcing this part by number, call us to confirm it matches your specific transmission model and configuration before ordering.FeaturesGenuine Eaton Fuller transmission componentPart number 228580Internal countershaft for Fuller heavy-duty manual transmission gear trainsSold by Pro Gear and TransmissionCall to confirm fitment for your specific transmission model