A lubricant composition includes a base oil present in an amount of greater than 70 parts by weight per 100 parts by weight of the lubricant composition and an antioxidant. The antioxidant has the structure: wherein each X is independently CH or N, so long as at least one X is N. A is an electron donating group that (1) has an atom having at least one lone pair of electrons that is bonded directly to the aromatic ring or (2) is an aryl or alkyl group. Z is chosen from a hydrogen atom and an electron donating group that has an atom having at least one lone pair electrons that is bonded directly to the aromatic ring or is an aryl or alkyl group.

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The present disclosure provides a lubricating oil composition which has a viscosity much lower than that of a conventional lubricating oil composition, and which is excellent in metal fatigue life, wear resistance and electrical insulating properties. The lubricating oil composition according to the present disclosure comprises: (A) a lubricating base oil; and (B) from 0.6 to 4.0% by weight, based on the total weight of the lubricating oil composition, of a polydiene having a number average molecular weight of from 500 to 3,000 and containing a functional group on at least one end thereof. The above described lubricating oil composition does not comprise a viscosity index improver, and has a kinematic viscosity at 100 C. of not less than 1 and less than 5 mm.sup.2/s.

The present disclosure describes a lubricating composition including a) a major part of a base oil of lubricating viscosity wherein the base oil is selected from API Group I, II, III, IV, V, or mixtures thereof, b) a total of 0.001 to 0.536 wt. %, based on the total lubricating composition, of one or more monohydrocarbyl-substituted dimercaptothiadiazole derivative(s) according to Formula (I), or a tautomer or salt thereof, below

##STR00001## wherein R is methyl or C.sub.2 to C.sub.4 alkyl, wherein the total lubricating composition has a sulfur content of up to 2,500 ppm (wt.), c) less than 0.1 wt % phosphite. The disclosure further describes the use of the lubricating composition for lubricating a driveline, a transmission including a manual or automated transmission, a gear, an automated gear, or an axle, and for enhanced FZG test performance. The disclosure further relates to a method for preparing the lubricating composition.

The invention provides a lubricating composition containing an antiwear agent and an oil of lubricating viscosity. The invention further relates to the use of the lubricating composition in an internal combustion engine, or a driveline device.

A lubricant composition comprising a) a synthetic poly-alpha-olefin base fluid; b) an organomolybdenum friction modifier; c) an alkylphosphorothiolate and a hydrocarbylamine anti-wear combination; and d) a dihydrocarbyl dithiophosphate extreme pressure additive and optionally one or more of e) a copper corrosion inhibitor; f) an anti-foam agent; g) a solubilizing agent; h) polymeric viscosity index improver; and i) an oligomeric viscosity modifier is highly suitable for use in the synchronizer of a transmission.

A lubricant composition includes a base oil present in an amount of greater than 70 parts by weight per 100 parts by weight of the lubricant composition and an antioxidant. The antioxidant has the structure: wherein each X is independently C-A or N, so long as at least one X is N but no more than two of X are N. Moreover, A is H, cyano or an electron donating group that: (1) has an atom having at least one lone pair of electrons that is bonded directly to the aromatic ring; or (2) is an aryl group or alkyl group. Further, each R is independently H, an alkyl group, or aryl group and each R is independently an alkyl group or an aryl group. ##STR00001##

A lubricant composition includes a base oil present in an amount of greater than 70 parts by weight per 100 parts by weight of the lubricant composition and an antioxidant. The antioxidant has the structure: wherein each X is independently CH or N, so long as at least one X is N. A is an electron donating group that (1) has an atom having at least one lone pair of electrons that is bonded directly to the aromatic ring or (2) is an aryl or alkyl group. Z is chosen from a hydrogen atom and an electron donating group that has an atom having at least one lone pair of electrons that is bonded directly to the aromatic ring or is an aryl or alkyl group. ##STR00001##

Provided is a mineral base oil having a kinematic viscosity at 40 C. of 4.0 mm.sup.2/s or more and less than 6.0 mm.sup.2/s, a kinematic viscosity at 100 C. of 1.0 mm.sup.2/s or more and less than 2.0 mm.sup.2/s, and a flash point of 140 C. or higher. A lubricating oil composition containing the mineral base oil has a high flash point while having a low viscosity and thus having excellent fuel-saving performance when used as a driving system oil and the like.

This invention provides A methacrylic copolymer (C) comprising 25 to 35 mass % of a methyl methacrylate unit (A), and 75 to 65 mass % of an alkyl methacrylate ester unit (B) containing an alkyl group having 10 to 36 carbon atoms, the methacrylic copolymer having (a) a weight average molecular weight of 10,000 to 500,000, (b) a molecular weight distribution (Mw/Mn) of 1.01 to 1.60, (c) a triad syndiotacticity (rr) of 65% or more, and (d) a solubility of 5.0 mass % or more at 0 C. in at least one lubricant base oil (D) selected from the group consisting of API groups III, III+, and IV.

The invention provides a lubricating composition containing an oil of lubricating viscosity and an ashless ketone compound with at least one of a hydroxy group and an ether linkage attached to the carbon atom adjacent to the carbonyl carbon of the ketone, especially -hydroxyketone. The invention further relates to methods of lubricating an internal combustion engine by supplying the described lubricating composition to the internal combustion engine. The invention further relates to the use of the -hydroxyketone compound as a friction modifier and an antiwear agent.