Strange Ford 9in S-Trac Differential

The Strange Ford 9in S-Trac Differential is engineered for serious street and strip performance, delivering superior traction control when you need it most. Built for Ford 9-inch rear housings, this differential solves the fundamental problem of open-diff wheel spin by locking the inside wheel during cornering and acceleration while allowing normal turning behavior on straights. Whether you're building a high-horsepower street machine, a bracket racing competitor, or a weekend warrior seeking predictable launch characteristics, the S-Trac offers the reliability and adjustability that modern hot rodders demand without the complexity of electronic systems.

Strange's S-Trac design uses a mechanical spool clutch mechanism that engages progressively based on load, providing partial lock during hard acceleration and releasing smoothly during deceleration and turning. This approach eliminates the violent chattering and binding that early limited-slip differentials produced, while maintaining instant torque bias when power is applied. The unit features precision-machined internals and durable clutch materials rated for sustained abuse, making it ideal for both naturally aspirated and forced-induction applications. At 17 pounds, the S-Trac is compact enough to fit standard 9-inch housings while delivering the locking performance of much heavier designs, preserving your suspension geometry and ride quality.

Fitment is universal for any Ford 9-inch differential housing, whether sourced from classic muscle cars, early Foxbodies, or modern Coyote swaps. Installation requires only standard differential work—no exotic tooling or modifications to your existing housing. The S-Trac excels in applications ranging from street strip combos and autocross platforms to dedicated drag cars, where consistent 60-foot times and predictable handling inspire confidence. Proper setup with quality synthetic gear oil and attention to break-in procedures ensures maximum service life and performance reliability.