Is it possible to have a Ford 9-inch without an annoying amount of gear whine? Of course, but at what cost? How much time and money are you going to spend chasing down the issue when you can now simply bolt an 8.8-inch center section into your 9-inch housing thanks to the engineers at DSE? Detroit Speed now offers five different gear ratios and a complete assembly that will bolt directly into your 9-inch housing. Complete with forged alloy steel carrier bearing caps, high-strength nodular case, safety wired ARP hardware, 1350 forged steel pinion yoke, and a 31-spline Eaton Truetrac differential, it's built to handle some serious power and deliver it quietly and more efficiently than any 9-inch. *The FN988 Case is compatible with all 8.8-inch gears, differentials, and spools. Alternate options are available. Contact us for custom builds or combinations not listed. *FN988 specific axles will be necessary and driveshaft will need to be shortened. Is it possible to have a Ford 9-inch without an annoying amount of gear whine? Of course, but at what cost? How much time and money are you going to spend chasing down the issue when you can now simply bolt an 8.8-inch center section into your 9-inch housing thanks to the engineers at DSE? Detroit Speed now offers five different gear ratios and a complete assembly that will bolt directly into your 9-inch housing. Complete with forged alloy steel carrier bearing caps, high-strength nodular case, safety wired ARP hardware, 1350 forged steel pinion yoke, and a 31-spline Eaton Truetrac differential, it's built to handle some serious power and deliver it quietly and more efficiently than any 9-inch. *The FN988 Case is compatible with all 8.8-inch gears, differentials, and spools. Alternate options are available. Contact us for custom builds or combinations not listed. *FN988 specific axles will be necessary and driveshaft will need to be shortened. 31 Spline Truetrac - 3.31 Ratio - 1350 Yoke with U-Bolts 31 Spline Truetrac - 3.31 Ratio - 1350 Yoke with U-Bolts