Collection: Auto - Transmission Oil

Maintain ideal shear stability under punishing thermal loads, prevent synchronizer grind across aggressive shift intervals, and lower friction wear on high-pressure internal gears with our selection of Auto Transmission Oil. At DIY Customs, we provide premium manual transmission gear oils, high-viscosity synthetic automatic drivetrain lubricants, specialized transaxle oils, and limited-slip additive fluids designed for a perfect fit on independent import and domestic manual gearboxes and early-model automatic platforms. Whether you are seeking a specialized friction-modified gear oil to completely cure harsh cold-weather shifting notchiness on a sports car, outfitting your shop bay with heavy-duty GL-4 or GL-5 fluid weights to protect high-torque commercial truck gears, or looking for premium multi-vehicle fluids that actively neutralize foam buildup under extreme rotational stress, our professional-grade maintenance supplies offer the exceptional film strength and corrosion protection you need at unbeatable prices. From raw layout maintenance adapters to premium fluid service accessories, we carry the ultimate automotive preservation supplies to extend the lifespan of your mechanical grid. Don't see your specific viscosity grade (like 75W-90, 80W-90, or Synchromesh), exact friction index modification, or specialized manufacturer fluid rating? Hit the live chat or call 412-882-8346—we can special order and drop-ship exactly what your transmission requires directly to your doorstep!