Big Bore XD2 Gearbox for 2007-18 Jeep JK Performance Components PSC SteeringPSC's Exclusive Big Bore XD2 Power Steering Gearbox is an essential, critical steering component for any Jeep JK with increased torque loads such as large tire sizes up to 37 Inches, locking front differentials, and larger aftermarket axles such as Currie, Dynatrac, and Teraflex. Applications: 2007 18 Jeep JK 2 Door or 4 Door Features: 85MM Piston for a 35 percent Increase in Torque Output to efficiently move large tire sizes up to 37 Inches, locking