Automotive and truck power train parts, namely, direct replacement and performance heavy duty front or rear axle shafts, spline enhancement axle shaft kits comprised of large splined alloy inner shafts with seals, outer alloy stub shafts, heavy duty upgraded universal joints for front applications, heavy duty large splined rear alloy axle shafts, bearings, seals and heavy duty wheel studs for rear applications for increase in strength and durability, direct replacement and performance heavy duty U-joint, performance heavy duty power drive oil seal, direct replacement and performance heavy duty ring and pinions, direct replacement and performance heavy duty differential covers; power train differential installation kits, comprised of ring bearings, housing bearings, oil seal, gaskets, pinion and housing shims, crush collars, liquid thread lock, marking compound, ring gear bolts, nuts, washers, oil slinger and baffles