This Yukon Mini spool is made for Ford 8.8″ with 31 Spline axles. (Part number YP MINSF8.8-31) Yukon Mini Spools are a low-cost traction option for vehicles looking for full-time lockup. The mini spool installs into a standard open carrier in place of the spider gears and delivers 100% power to both tires at all times. These units are not recommended for street-driven vehicles. Full spools are recommended for vehicles with large tires or high horsepower. Yukon performance spools are made from the highest quality materials to ensure high strength and long life in performance applications.