Enhancement of frictional retention properties in a lubricating composition containing a molybdenum sulfide additive in low concentration

The invention is a method for improving the friction reduction and friction reduction retention performance of a lubricating oil comprising adding to the lubricating oil a trinuclear molybdenum sulfur compound selected from the group of trinuclear molybdenum compounds preferably those having the formulas Mo3S7(dtc)4 and Mo3S4(dtc)4 and mixtures thereof wherein dtc represents independently selected diorganodithiocarbamate ligands containing independently selected organo groups and wherein the ligands have a sufficient number of carbon atoms among all the organo groups of the compound's ligands are present to render the compound soluble or dispersible in the lubricating oil. Concentrates of the composition are also included in the invention.