Remanufactured Axle Assembly, 3.73 Ratio, Rear Drum

The Zumbrota RAA435-2031C is a remanufactured axle assembly engineered to meet the highest standards of precision and reliability for your 1999 Ford F-150. This assembly features a 9.75-inch ring gear and a 3.73 gear ratio, designed specifically for models with rear drum brakes. Zumbrota Drivetrain meticulously inspects each unit for straightness, cracks, and surface wear. All internal components undergo rigorous testing, including ring and pinions, internal gears, clutches, and carriers. To ensure longevity and optimal performance, all bearings and seals are replaced, and gears are inspected for proper tooth contact patterns and rolling torque. Correct gear backlash is set for adequate lubrication and quiet operation, while axle tubes are checked to meet OEM standards for straightness. The remanufacturing process includes an exclusive hydro-blast rinse, sandblasting, and a proprietary shot-enticed deep cleaning procedure. Key specifications include a Ford-built component, Hollander No. 435-231C, 12 MM wheel studs, and 2.533 OD wheel bearings. This model is for applications without Posi Traction, has a semi-floating axle type, and includes the cover. It requires the use of the *Check Tag* designation for proper fitment verification.