9-Inch - Currie TwinTrac (31-Spline)

Currie TwinTrac^® Helical-gear limited-slip differential (LSD) is the modern replacement for the classic clutch-style Posi. Under normal driving conditions, the TwinTrac operates like an open differential, allowing the wheels to spin at different speeds to negotiate turns smoothly. However, when accelerating, if a tire begins to lose traction, the helical gears inside the TwinTrac automatically engage, applying power to both rear wheels. When the acceleration (torque) lessens, the differential resumes regular operation. The TwinTrac is maintenance-free and will maintain its high torque bias for life, as it does not rely on clutches or springs that wear out.