Check the listing for details. Precision Gear Ford 9 inch 4.71 Ring & Pinion with 31 Spline Spool Ultralight Se. Condition: New other (see details). Listed at 189.00 USD. New Precision Gear Ultra Light Series 4.71 Ring and Pinion and 31 spline spool for 9 inch Fordmade in the USA ring & pinion Fits 2.89" Stock 9" Ford Case & 3.06" Stock Ford and Aftermarket Center Section Bearing Journals for 1.781" ID Carrier Bearings, usually 28 or 31 spline cases. You must have the matching spool and ring & pinion since they are different than other manufacturers.Stock Photo. ** NO RETURNS **MADE FROM THE HIGhest quality materials to ensure high strength and long life in performance applications. Spools provide 100% power to both tires at all times and are a lower cost alternative to lockers. Spools are not recommended for street driven vehicles.ABOUT PRECISION GEARTom Reider was the founder of Precision Gear. He began racing in the 1950’s and raced until 1986 when he started Precision Gear. Precision Gear started in the drag racing business, but soon moved into VW and Corvair transaxles, and then into off road and NASCAR applications. As the business began to grow Tom made the decision to go into business for himself, leaving is job at Ford. Shipping only in the 48 states USA.