This invention encompasses lubricating oil compositions comprising a base oil, a biodiesel fuel and a dispersant. A method for inhibiting viscosity increase in a diesel engine fueled at least in part with a biodiesel fuel is also described.

Oil compositions derived from transgenic soybeans having a high concentration of oleic acid are described for use in various applications including use to enhance the low temperature pour characteristics of engine fluids. Such oil compositions are useful as lubricants, rail curve grease and engine penetrants.

A vehicle system, comprising an internal combustion engine, a transmission enclosed within a transmission case coupled to a gaseous fuel source, the transmission case having an amount of gaseous fuel located therein. Housing the transmission in a case containing low density gaseous fuel reduces the power losses from air resistance and increases fuel efficiency.