The present invention provides a lubricating oil additive, including: a molybdenum compound (A) represented by the following general formula (1); and a sulfur-based composition (B) containing a sulfur-based compound (b-1) represented by the following general formula (2) and at least one kind of sulfur-based compound (b-2) represented by the following general formula (3) or (4), and a lubricating oil composition containing the additive. In the formula (1), R.sup.1 to R.sup.4 each represent alkyl groups having 6 to 18 carbon atoms, the groups being identical to or different from each other, and X.sup.1 to X.sup.4 each independently represent an oxygen atom or a sulfur atom. In the formula (2), R.sup.5 represents an alkyl group having 1 to 22 carbon atoms, R.sup.6 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, R.sup.7 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and “a” represents a number from 1 to 10. In the formulae (3) and (4), R.sup.8 to R.sup.11 each represent alkylene groups having 1 to 28 carbon atoms, the groups being identical to or different from each other, R.sup.12 and R.sup.13 each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and “b” and “c” each independently represent a number from 1 to 8, provided that at least one of R.sup.12 or R.sup.13 represents an alkyl group having 1 to 3 carbon atoms.

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In the field of lubricating compositions, in particular to the Fuel Economy (FE) properties of lubricating compositions, there is disclosed the combined use of at least one derivative of molybdenum and at least one derivative of boron to maintain the Fuel Economy (FE) properties of a lubricating composition also including at least one base oil. Also disclosed is a use, within a lubricating composition including at least one base oil, of a combination of at least one derivative of molybdenum and at least one derivative of boron, and at least 30 ppm and at most 600 ppm of born boron relative to the weight of the lubricating composition to preserve the Fuel Economy (FE) properties of this lubricating composition.

Lubricant compositions comprising a base oil, one or more antioxidants selected from a group consisting of N-α-naphthyl-N-phenylamine antioxidants and diphenylamine antioxidants; and a sulfur-containing additive comprising up to seven carbon atoms exhibit outstanding oxidative stability and non-corrosion properties. The N-α-naphthyl-N-phenylamine antioxidants plus diphenylamine antioxidants in total may be present from about 0.2 wt % to about 0.8 wt %, based on the total weight of the lubricant composition. The sulfur provided by the sulfur-containing additive may be present from about 50 ppm to about 1000 ppm by weight, based on the total weight of the lubricant composition.

Lubricating compositions comprising a thiol-carboxylic adduct that is the reaction product of a thiol and carboxylic acid and/or a carboxylic acid derivative. The lubricating composition also comprises an antiwear agent. Methods of lubricating an internal combustion engine comprise contacting the internal combustion engine with a lubricating composition comprising a thiol-carboxylic adduct that is the reaction product of a thiol and carboxylic acid and/or a carboxylic acid derivative. Methods of reducing lubricant oxidation and/or corrosion in an internal combustion engine with a lubricating composition comprising a thiol-carboxylic adduct that is the reaction product of a thiol and carboxylic acid and/or a carboxylic acid derivative. The use of a comprising a thiol-carboxylic adduct that is the reaction product of a thiol and carboxylic acid and/or a carboxylic acid derivative to reduce lubricant oxidation and/or corrosion in an internal combustion engine.

Thioether-substituted phenols that are the reaction product of a thioether-substituted alcohol or thioether-substituted amine and a phenol with at least one pendant acyl group and have a ratio of sulfur groups to phenol groups of at least 1:1 and uses for thioether-substituted phenols. Methods of lubricating an internal combustion engine by contacting the internal combustion engine with a lubricating composition comprising a thioether-substituted phenol. Methods of reducing deposit formation and/or corrosion in an engine using a lubricating composition comprising a thioether-substituted phenol.

A lubricating oil composition comprising at least 50 percent by mass, based on the mass of the composition of an oil of lubricating viscosity and 0.01 to 25 percent by mass, based on the mass of the composition of a polymer comprising units (a) and one or both units (b) and (c):

N(COR.sup.1)(CH.sub.2).sub.x(a)

NH(CH.sub.2).sub.y(b)

N(CH.sub.2CH.sub.2-k(CH.sub.3).sub.kCOOR.sup.2)(CH.sub.2).sub.z (c) where the total number (n) of units (a), (b) and (c) is an integer between 4 and 500; wherein x, y and z are independently 2 or 3; wherein k is zero or 1. The polymer shows good solubility in the lubricating oil and provides friction modification. A method of synthesising a polymer is also disclosed.

Provided is a grease composition for a magnet clutch of an automobile, including: a base oil; and a thickener, wherein the composition contains 5% by mass or more of a sulfur content in terms of sulfur element relative to a total mass of the composition.

Lubricant compositions comprising a base oil, one or more antioxidants selected from a group consisting of N--naphthyl-N-phenylamine antioxidants and diphenylamine antioxidants; and a sulfur-containing additive comprising up to seven carbon atoms exhibit outstanding oxidative stability and non-corrosion properties. The N--naphthyl-N-phenylamine antioxidants plus diphenylamine antioxidants in total may be present from about 0.2 wt % to about 0.8 wt %, based on the total weight of the lubricant composition. The sulfur provided by the sulfur-containing additive may be present from about 50 ppm to about 1000 ppm by weight, based on the total weight of the lubricant composition.

Thioether-substituted phenols that are the reaction product of a thioether-substituted alcohol or thioether-substituted amine and a phenol with at least one pendant acyl group and have a ratio of sulfur groups to phenol groups of at least 1:1 and uses for thioether-substituted phenols. Methods of lubricating an internal combustion engine by contacting the internal combustion engine with a lubricating composition comprising a thioether-substituted phenol. Methods of reducing deposit formation and/or corrosion in an engine using a lubricating composition comprising a thioether-substituted phenol.

The present invention provides a lubricating oil composition for a transmission which is excellent in seizure resistance and copper corrosion resistance, and which contains a base oil (A), a sulfur-containing compound (B) having no S.sub.n11 (where n.sub.11 is an integer of 2 or more), and a thiadiazole compound (C) having an S.sub.n2113 R.sup.21 group (where R.sup.21 is a linear hydrocarbon group having 1 or more and 24 or less carbon atoms, and n.sub.21 is 1 or 2), a method for lubricating a transmission, including using the same, and a transmission provided with the same.