6.66 Ratio 9in Ford AX

The 6.66 Ratio 9in Ford AX ring and pinion kit from MOTIVE GEAR is engineered for Ford 9-inch differentials requiring precise gear reduction for enhanced torque multiplication and acceleration. This AX series component is built for street performance, drag racing, and off-road applications where aggressive gearing improves launch characteristics and overall driveline responsiveness. The 6.66:1 ratio delivers significant low-end power gains, making it ideal for high-horsepower builds, heavy-duty towing, or enthusiasts seeking noticeable performance improvements over stock configurations.

This kit features a 28-spline pinion shaft design that provides robust load-carrying capability and repeatable engagement with the ring gear. The AX series construction utilizes precision-cut gear teeth optimized for minimal backlash and maximum efficiency, reducing noise and vibration while maximizing power transfer from driveshaft to wheels. MOTIVE GEAR's manufacturing process ensures tight tolerances and superior durability under sustained high-load conditions, making this ratio suitable for modified engines and aggressive driving scenarios. The complete kit includes both ring and pinion gears, simplifying installation and ensuring perfect gear pairing from the factory.

Drivers upgrading Ford 9-inch differentials—whether for classic muscle cars, modern hot rods, or performance trucks—benefit significantly from this ratio's acceleration and pulling power. The 6.66:1 gear set works best with performance-oriented vehicles running higher RPM engines and modern transmissions capable of handling aggressive shifts. Installation requires proper differential service tools and understanding of backlash and preload adjustment; professional installation is recommended to ensure optimal performance and longevity. This component is compatible with all standard Ford 9-inch differential housings with 28-spline pinion requirements.