A lubricant composition of 40 to 95% of an oil having a kinematic viscosity at 100 DEG C of 3 to 7.5; 0.3 to 2 % of an amine salt of a phosphorus compound obtained by reacting phosphorus pentasulfidewith one or more alcohols having 4 to about 13, or 4 to 8, or 6, carbon atoms, with an alkylene oxide, and further with phosphorus pentoxide, and salting the resulting material with one or more amineshaving 2 to 20 or 12 to 24 carbon atoms; and an active-sulfur containing agent in an amount to provide 0.5 to 7% of sulfur to the composition provides good wear protection to gears at a relatively low viscosity of the composition.