9in Gear Full Spool 6.33 Ratio New Center Section

The 9in Gear Full Spool 6.33 Ratio New Center Section from PEM is a precision differential case assembly engineered for Ford 9-inch differentials demanding maximum traction in high-performance and heavy-duty applications. This steel spool center section replaces worn or stock differentials, locking both axle shafts together to eliminate wheel slip during acceleration, cornering, and load transfer. Designed for street rods, drag racing, off-road vehicles, and heavy hauling, this component delivers predictable power delivery when traction control is your priority.

Built as a fully assembled center section, the 9in Gear Full Spool features a 6.33 gear ratio and 31-spline design, offering direct compatibility with Ford 9-inch housings. The steel spool construction provides unmatched durability and rigidity compared to clutch-type differentials, eliminating maintenance concerns associated with friction materials and fluid dynamics. The 6.33 ratio delivers aggressive acceleration characteristics—ideal for vehicles prioritizing low-end torque multiplication over highway cruising efficiency. Its natural finish protects against corrosion while the assembled design minimizes installation complexity, requiring only axle shaft installation and housing bolting.

This center section suits rebuilders, hot rod fabricators, and performance enthusiasts upgrading tired differentials or converting to full-spool traction. The 31-spline interface pairs with OEM and aftermarket Ford 9-inch axle shafts of matching spline count. At 73.3 lbs and measuring 15.3 x 15.3 x 21 inches, installation requires standard differential service expertise—drain, remove old case, install new center section, reinstall axles, and refill with gear oil. Verify your Ford 9-inch housing serial number and spline count before purchase to ensure proper fitment.