Currie TwinTrac® helical gear style limited slip differential for 9-inch rearends
Due to limited availability, the TwinTrac is only available in complete third members and rearends
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.