Antioxidant combinations of sulfur containing molybdenum complexes and aromatic amine compounds for lubricating oils

A lubricating oil additive comprising a combination of

• (a) an oil soluble sulfur containing molybdenum complex prepared by (1) reacting an acidic molybdenum compound and a basic nitrogen compound selected from the group consisting of a succinimide, carboxylic acid amide, Mannich base, phosphonamide, thiophosphonamide, phosphoramide, dispersant viscosity index improvers, or mixtures thereof to form a molybdenum complex wherein from 0.01 to 2 atoms of molybdenum are present per basic nitrogen atom, and (2) reacting said complex with carbon disulfide in an amount to provide 0.1 to 4 atoms of sulfur per atom of molybdenum, and
• (b) an oil soluble aromatic amine compound or mixtures thereof, wherein the aromatic amine compound of component (b) is present in an amount of from 0.02 to 10 parts by weight per part by weight of the sulfur containing molybdenum complex of component (a).