Information?? High quality chassis partseries products. Made with high strength steel tubing for superior strength and durability. Stable performance, reliable quality and long service life Uniform thickness, no blow holes, slag, cracks, tearing, or incomplete fusion. Measured by specialized inspection tools after welding to make sure assemble hole , bushings insert, and installation sizes are proper. Professional InstallerisHighly Recommended(No Instruction Included) Alignment Highly Recommended After InstallCompatibility Chart?? For FordPackage Content?? 1*8″ 4-Pinion Trac-Lock Posi Unit (28 Spline)