Motive Gear F10.25IK Differential Install Kit for Ford 10.25", 12-Bolt, Mini-Kit - Fits Ford F-250/F-350 (1985-1998), Replaces: Ratech 121K, Richmond Gear 83-1059-B, Yukon Gear MK F10.25

Short Summary: The Motive Gear F10.25IK is a premium differential install kit for Ford 10.25" rear axles (12-bolt), covering Ford F-250 and F-350 trucks from 1985 to 1998. It includes all essential components needed for a professional-grade rebuild or gear install.Key FeaturesAxle Fitment: Ford 10.25" (12-Bolt)Gear Ratio Compatibility: 4.89 (Example)Pinion Gear Tooth Count: 8Ring Gear Tooth Count: 39Pinion Shaft Diameter: 1.94 InchesPinion Spline Count: 31Kit Components: Crush Sleeve or Shim Pack, Cover Gasket or RTV, Pinion Seal, Pinion Nut, Ring Gear Bolts, Pinion & Carrier Shims, Thread Locker, Marking Compound, BrushVehicle CompatibilityFits Ford 10.25" Rear Differentials in the following models:Ford1985–1998 F-2501985–1998 F-350Replaces OEM & Aftermarket Part NumbersRatech: 121KRichmond Gear: 83-1059-BYukon Gear & Axle: MK F10.25Warranty & Quality AssuranceBacked by a 1-Year / 50,000-Mile Warranty, Motive Gear install kits are engineered for reliability and OE-level performance. Trusted by professionals and enthusiasts alike, Motive Gear delivers consistent quality and dependable drivetrain solutions.

• Designed for Ford 10.25" rear axles with a 12-bolt differential cover; perfect for rebuilding differentials on F-250 and F-350 models from 1985 to 1998.
• Kit includes: cover gasket or RTV, crush sleeve or preload shim pack, pinion nut, pinion seal, ring gear bolts, pinion and carrier shims, marking compound, thread locking compound, and brush.
• Built to OE standards for long-lasting performance and gear alignment—ideal for light-duty truck applications and gear replacement or upgrades.
• Compatible with gear sets featuring 8 pinion teeth, 39 ring teeth, 1.94" pinion shaft diameter, and 31-spline pinion design; designed to support 10.25" ring gear outer diameter.
• Backed by Motive Gear’s 1-year or 50,000-mile limited warranty, ensuring reliability and support for demanding driveline rebuilds.