High tensile strength 4140 Chromoly is heat-treated, tempered and induction hardened to produce these heavy-duty axles that are up to 35 percent stronger than stock 1040 axles. Alloy USA uses the latest cold rolled splining technology, to produce splines that are stronger than traditional cut splines. Our shafts are covered by an exclusive 10-year warranty! Rear axle shaft kits include everything you need for your installation: both passenger and drive side shafts, seals, bearings and wheel studs. These kits also come with Lockers.