A lubricating oil composition for a transmission, the composition including: (A) a lubricant base oil comprising a mineral base oil and/or a synthetic base oil; and (B) a poly(meth)acrylate having a weight average molecular weight of no more than 25,000, wherein the composition has a kinematic viscosity at 100° C. of 2.5 to 4.9 mm.sup.2/s.

A lubricant composition for a resin-resin sliding portion or a resin-metal sliding portion that contains a base oil containing a perfluoropolyether oil including a side chain, and a polytetrafluoroethylene having a primary particle diameter of 1 μm or larger and a melamine cyanurate as thickeners.

The present invention addresses a problem of providing a grease composition containing a urea-based thickener and capable of appropriately maintaining the kinematic friction force in lubrication parts. The grease composition contains a base oil (A) and a urea-based thickener (B), wherein the base oil (A) has a kinematic viscosity at 40° C. of 100 mm.sup.2/s or more, and the particles containing the urea-based thickener (B) in the grease composition satisfy the following requirement (I). Requirement (I): the area-based arithmetic average particle diameter of the particles is 2.0 μm or less, as measured by a laser diffraction/scattering method.

The present invention relates to a lubricating composition for an engine, in particular for a motor vehicle engine, comprising at least one base oil and at least one compound able to release formaldehyde under the temperature and pressure conditions of the combustion chamber of the engine. It also relates to the use, in a lubricating composition intended for an engine, of a compound able to release formaldehyde under the temperature and pressure conditions of the combustion chamber of the engine, as an additive for preventing and/or reducing pre-ignition, in particular low-speed pre-ignition (LSPI).

A lubricating oil composition for a transmission, the composition including: (A) a lubricant base oil comprising a mineral base oil and/or a synthetic base oil; and (B) a poly(meth)acrylate having a weight average molecular weight of no more than 25,000, wherein the composition has a kinematic viscosity at 100° C. of 2.5 to 4.9 mm.sup.2/s.

A booster additive concentrate may advantageously contain: (a) an anti-wear mixture of two or more phosphite/phosphate compounds and one or more ether/thioether compounds; (b) an ashless dispersant; (c) a calcium-containing detergent, such as an overbased calcium phenate; (d) ≥2 friction modifiers, at least one of which comprises a polyalkylene polyamine succinimide derivative; (e) optionally a corrosion inhibitor; and (f) a lubricating oil basestock. Based on these additive components, the booster additive concentrate may exhibit specific contents of B/Ca/P and may contain minimal or substantially no additional antioxidants. Lubricant compositions can be made from the booster additive concentrates and a fresh/used lubricant oil composition “diluent,” which can rejuvenate the diluent. Such lubricant compositions can have advantageous anti-shudder durability (ASD) lifetimes and other frictional properties. In particular, such concentrates/compositions can offer superior lubrication when used in vehicles with continuously variable transmissions (CVTs).

A lubricating grease composition containing a base oil having a kinematic viscosity of 10 mm.sup.2/s or more and 60 mm.sup.2/s or less at 40° C.; a thickener containing at least one soap selected from a metal soap and a metal complex soap; and a solid lubricant containing porous polyamide particles. An amount of the porous polyamide particles blended is 1% by mass or more and 20% by mass or less based on a total mass of the lubricating grease composition.

A booster additive concentrate may advantageously contain: (a) an anti-wear mixture of two or more phosphite/phosphate compounds and one or more ether/thioether compounds; (b) an ashless dispersant; (c) a calcium-containing detergent, such as an overbased calcium phenate; (d) ≥2 friction modifiers, at least one of which comprises a polyalkylene polyamine succinimide derivative; (e) optionally a corrosion inhibitor; and (f) a lubricating oil basestock. Based on these additive components, the booster additive concentrate may exhibit specific contents of B/Ca/P and may contain minimal or substantially no additional antioxidants. Lubricant compositions can be made from the booster additive concentrates and a fresh/used lubricant oil composition “diluent,” which can rejuvenate the diluent. Such lubricant compositions can have advantageous anti-shudder durability (ASD) lifetimes and other frictional properties. In particular, such concentrates/compositions can offer superior lubrication when used in vehicles with continuously variable transmissions (CVTs).

Disclosed is a lubricating oil composition capable of inhibiting vibrations or noises generated between a pulley and a chain or between a pulley and a belt in a CVT or the like, while increasing an intermetallic friction coefficient, the composition containing a base oil, an alkaline earth metal-based detergent (A), a phosphite ester (B1), a phosphate ester amine salt (B2), an acidic phosphate ester (B3), an aliphatic monoamine (C1), and an aromatic monoamine (C2).

Provided are: a lubricating oil composition containing a mineral oil (A) having a kinematic viscosity at 40° C. of 5 to 15 mm.sup.2/s and a flash point of 180° C. or higher, a synthetic oil (B) having a kinematic viscosity at 40° C. of 5 to 15 mm.sup.2/s and a flash point of 190° C. or higher, an amide compound (C) and a polyol ester compound (D), which has a low viscosity and fuel saving performance, which can be used in high-temperature environments, and which has excellent gear anti-seizing property and anti-shudder performance; and a lubrication method and a transmission using the lubricating oil composition.