The Speedmaster 1-215-001-09 is a complete Ford 9-inch third member assembly built around a 4.88:1 ring-and-pinion ratio, featuring a helical gear limited-slip differential and a lightweight aluminum case. The 28-spline LSD delivers smooth, progressive torque transfer to both rear wheels without the harsh engagement associated with traditional clutch-pack units, making it an excellent upgrade for street performance and strip-duty applications alike.
Designed as a direct-fit replacement for Ford 9-inch rear axle housings, this third member assembly offers a ready-to-install solution that simplifies the build process and reduces downtime. The aluminum housing helps shed rotational and unsprung weight compared to a cast-iron unit, while the helical LSD requires no special friction modifier additives, keeping long-term maintenance straightforward.
