Redline Oil, Redline, Red Line, 58104, Full Synthetic, GL5, GL-5, Differential Gear Oil, 80W140, 80W-140, API, GL6, GL-6, MT1, MT-1. SAE Viscosity Grade (Gear Oil) 80W140. API Service Class GL 5+. Superior shear stability and reduced oxidation compared to other synthetics and conventional gear oils.