Abstract: A fluid includes a base stock and one or more additives. The base stock has a viscosity index of at least 80, and either a kinematic viscosity at 40° C. of at least 320 cSt or a kinematic viscosity at 100° C. of at least 14 cSt. The base stock includes greater than or equal to about 90 wt % saturates, less than or equal to about 10 wt % aromatics, and a sum of terminal/pendant propyl groups and terminal/pendant ethyl groups of at least 1.7 per 100 carbon atoms. The fluid has a thermal conductivity measured according to ASTM D7896 at 140° C. of 0.12 W/m·K or greater.

Abstract: This disclosure relates to a lubricating oil (e.g., gear oil) for use in an electric or hybrid vehicle. The lubricating oil has a composition including one or more lubricating oil base stocks as a major component, and one or more lubricating oil additives, as a minor component. The one or more lubricating oil base stocks include at least one Group IV base oil, or at least one Group V base oil. The lubricating oil has a kinematic viscosity (KV100) from 1 cSt to 7 cSt at 100° C. as determined by ASTM D-445, and an electrical conductivity at room temperature of less than 15,000 pS/m as determined by ASTM D-2624. This disclosure also relates to methods for producing a lubricating oil for a transmission, gear train, gear set, gear box, or gears of an electric vehicle powertrain and methods for improving energy efficiency, while maintaining or improving wear control.

Abstract: A fluid includes a base stock and one or more additives. The base stock has a viscosity index of at least 80, and either a kinematic viscosity at 40° C. of at least 320 cSt or a kinematic viscosity at 100° C. of at least 14 cSt. The base stock includes greater than or equal to about 90 wt % saturates, less than or equal to about 10 wt % aromatics, and a sum of terminal/pendant propyl groups and terminal/pendant ethyl groups of at least 1.7 per 100 carbon atoms. The fluid has a thermal conductivity measured according to ASTM D7896 at 140° C. of 0.12 W/m·K or greater.

Abstract: This disclosure relates to a lubricating oil (e.g., gear oil) for use in an electric or hybrid vehicle. The lubricating oil has a composition including one or more lubricating oil base stocks as a major component, and one or more lubricating oil additives, as a minor component. The one or more lubricating oil base stocks include at least one Group IV base oil, or at least one Group V base oil. The lubricating oil has a kinematic viscosity (KV100) from 1 cSt to 7 cSt at 100° C. as determined by ASTM D-445, and an electrical conductivity at room temperature of less than 15,000 pS/m as determined by ASTM D-2624. This disclosure also relates to methods for producing a lubricating oil for a transmission, gear train, gear set, gear box, or gears of an electric vehicle powertrain and methods for improving energy efficiency, while maintaining or improving wear control.