The Ford 8.8- and 9-inch rear differentials are two of the most popular and best-performing differentials on the market. While the 8.8-inch differential is commonly used in late-model Mustangs, the 9-inch is the more popular and arguably the most dominant high-performance differential for muscle cars, hot rods, custom vehicles, and race cars. Built from 1957 to 1986, the 9-inch Ford differential is used in a huge range of high-performance Ford and n-Ford vehicles because of its rugged construction, easy-to-set-up design, and large aftermarket support. The 9-inch differential effectively transmits power to the ground for many classic Fords and hot rods of all types, but it is the choice of many GM muscle car owners and racers as well. These differentials have been used extensively and proven their mettle in racing and high-performance applications. The Ford 8.8- and 9-inch must be rebuilt after extensive use and need a variety of different ratios for top performance and special applications. This Workbench book provides detailed step-by-step photos and information for rebuilding the differentials with the best equipment, installing the gear sets, and converting to Posi-Traction for a variety of applications. It describes how to disassemble the rear end, identify worn ring and pinion gears, other damage or wear, and shows step-by-step rebuilding of the differential. It also explains how to select the right differential hardware, bearings, seals, and other parts, as well as how to set ring and pinion backlash so that the rear end operates at peak efficiency. Aftermarket 9-inch performance differentials from manufacturers including Currie, Moser and Strange are reviewed and you learn how to rebuild and set up these high-performance aftermarket differentials. In addition, this book provides a comprehensive identification chart to ensure readers properly identify the model and specifics of the 9-inch differential. Chapters include axle identification, inspection, and purchasing axles for rebuilding; differential tear down; ring and pinion gear removal; inspection and reassembly; drive axle choices; and more.