We predominantly use five metal types; 4320, 4340, 8620, 9310, and 1541H.
4300-series is a nickel-chromium-molybdenum alloy, i.e. chromoly, that’s low in carbon content. 4320 is used for the internals in our line of Yukon Dura Grip LSDs. We use 4340 in the manufacturing of forged gears, pinion gears, high-performance axles, Super Joints, and more. 8620 is a low-nickel alloy steel generally used in the manufacture of forged camshafts, crankshafts, and fasteners. We use it in gears and cases. 9310 is an alloy steel with more nickel and chromium than 8620. 9310 can better endure high shock loads without failing and we use it in Spartan Lockers. 1541H is a high-grade carbon steel used in our replacement axles and u-joints, and similar products. A caveat here, heat-treating plays a definitive role in a given alloy’s hardness and other properties that impact their performance in automotive drivetrain applications. We use advanced heat-treating techniques to fine tune our alloys to their intended usage.