These products contain the extreme pressure additives necessary for ultimate protection road cars and racing vehicles, as well as friction modifiers for proper limited-slip operation Fully-synthetic formulas created from polyol ester base stocks, offer excellent lubrication under extreme conditions. High viscosity-index (VI) to provide relatively constant viscosity and film thickness with varying temperature change. Ester base stocks and friction modifiers provide additional slipperiness to lower operating temperatures by reducing the sliding friction in hypoid gears Details: Sold as 1 Gallon Superior shear stability and reduced oxidation compared to other synthetics and conventional gear oils Exceed API GL-5 specifications Engineered to provide the highest degree of protection and improvement of differential efficiency for better mileage, longer drain intervals, and less wear Contains extreme pressure additives like our 75W140 GL-5 oil, but lacks friction modifiers to balance slipperiness Popular for historic and vintage transmissions, like Mid-1930s to early-1950s synchro-equipped gearboxes in cars and trucks Helps with noisy or rough shifting in troubled A-833 Dodge/Plymouth 4-speed transmissions from 1964 to 1969 Option for noisy transmissions when mixed with 75W90NS or MT-90 to bring viscosity level up Also used in clutch-type limited slip differentials in racing for maximum lock up-some users add Limited Slip Friction Modifier in small doses to customize slippage API Service Class GL 5 Plus SAE Viscosity Grade (Gear Oil) 75W140 Vis at 100 degrees C, CSt 26.9 Vis at 40 degrees C, CSt 179 Viscosity Index 188 Pour Point, degrees C neg 45 Pour Point, degrees F neg 49 Brookfield Viscosity, Poise 1200 at neg 40 degrees C