1. The AxleTech portal boxes have four gears inside, each 60 mm wide (2.36 inches) and made of heat-treated 8620 steel. The upper drive gear has an internal 35-spline that receives the new stub shaft. The bottom drive gear has a 41-spline, 53mm-diameter (2.09-inch) output to the drive flange where the wheel mounts. The gear multiplies the axle ring-and-pinion ratio by 1.5, such that 5.38 now equals 8.07, thus reducing stress on axleshafts, U-joints, and everything upstream.