Improving chipping resistance of transmission lubricating compositions useful e.g. as lubricant for vehicle transmissions, comprises adding compounds reducing of active sulfur, to the initial transmission lubricating composition

摘要

Process for improving chipping resistance of transmission lubricating compositions containing sulfur compounds and phosphosulfur compounds, comprises adding compounds reducing at least 5 mass% of active sulfur measured by ASTM D1662 in the final composition, to the initial transmission lubricating composition. An independent claim is included for a lubricating composition comprising: base oils (60-90 wt.%) of mineral, synthetic or natural origin; an anti-wear and extreme pressure phosphorus-sulfur and phosphorus additive; and an anti-wear and extreme pressure sulfur additive, where the ratio of the mass content of sulfur element (measured by ASTM D2622) and the mass content of phosphorus element (measured by ASTM D5185) of the lubricating composition is 20-40, preferably 25-35, and the ratio of the mass content of sulfur and the mass content of sulfur element of the lubricating composition is less than 0.34, preferably less than 0.33.