Twin Trac Differential 3rd Member, 31 Spline, Ford 9", 350 Gear Ratio Currie Sportsman 9-inch nodular iron gear case with 3.062 bore carrier bearings for 31-spline axles Nodular iron big bearing pinion support 1330 series short nodular iron pinion yoke Fully assembled and set up in-house by skilled professionals NEVER run a synthetic oil in a Currie rear end! See CE-9013 for a quality petroleum based oil option.