Abstract THIS INVENTION RELATES TO AN ADDITIVE WHICH WHEN ADDED TO NOT ONLY A SYNTHETIC ESTER LUBRICANT BUT ALSO A MINERAL, ANIMAL OR VEGETABLE LUBRICATING OIL CONFERS LOAD CARRYING PROPERTIES, AND WHICH IS NON-CORROSIVE, DOES NOT HAVE DELETERIOUS EFFECTS ON SILICONE RUBBERS, AND IS HYDROLYTICALLY STABLE. SUCH A LUBRICANT COMPOSITION COMPRISES A MAJOR PROPORTION BY WEIGHT OF A LUBRICATING OIL, A MINOR PROPORTION BY WEIGHT OF AN AMINE SALT OF A HALOGEN SUBSTITUTED CARBOXYLIC ACID WHEREIN THERE IS AT LEAST ONE HALOGEN ATOM IN THE ALPHA POSITION, AND A MINOR PROPORTION BY WEIGHT OF AN ANTIOXIDANT. PREFERABLY SUCH LUBRICANT COMPOSITIONS ALSO CONTAIN A MINOR PROPORTION BY WEIGHT OF A CORROSION INHIBITOR.