A lubricant composition containing a base oil, an alkyl benzene sulfonate metal salt, and an alkyl naphthalene sulfonate metal salt, wherein a total content of the alkyl benzene sulfonate metal salt and the alkyl naphthalene sulfonate metal salt is 1 to 2.2% by mass, and a mass fraction of the alkyl benzene sulfonate metal salt to a total mass of the alkyl benzene sulfonate metal salt and the alkyl naphthalene sulfonate metal salt is 0.3 or more.

A lubricant composition containing a base oil, an alkyl benzene sulfonate metal salt, and an alkyl naphthalene sulfonate metal salt, wherein a total content of the alkyl benzene sulfonate metal salt and the alkyl naphthalene sulfonate metal salt is 1 to 2.2% by mass, and a mass fraction of the alkyl benzene sulfonate metal salt to a total mass of the alkyl benzene sulfonate metal salt and the alkyl naphthalene sulfonate metal salt is 0.3 or more.

A lubricating oil composition may include a base oil (A), a zinc dithiophosphate (B) comprising a compound (B1) of formula (b-1), calcium sulfonate (C), and a seal sweller (D). In formula (b-1), R.sup.1 to R.sup.4 are each independently an alkyl group. However, at least one of R.sup.1 to R.sup.4 is a prescribed straight-chain alkyl group, and at least one of R.sup.1 to R.sup.4 is a prescribed branched chain alkyl group.

A lubricating oil composition may include a base oil (A), a zinc dithiophosphate (B) comprising a compound (B1) of formula (b-1), calcium sulfonate (C), and a seal sweller (D). In formula (b-1), R.sup.1 to R.sup.4 are each independently an alkyl group. However, at least one of R.sup.1 to R.sup.4 is a prescribed straight-chain alkyl group, and at least one of R.sup.1 to R.sup.4 is a prescribed branched chain alkyl group.

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 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 transmission fluid composition contains a major amount of a lubricating oil basestock, and a minor amount of an additive package comprising: (i) a mixture comprising two or more phosphites and/or phosphates; (ii) one or more thioester compounds; (iii) one or more zinc dihydrocarbyl dithiophosphate compounds; and (iv) one or more oil-soluble or dispersible molybdenum-containing compounds. Such a transmission fluid may be used for controlling and/or reducing wear, e.g., in a manual transmission.

A transmission fluid composition contains a major amount of a lubricating oil basestock, and a minor amount of an additive package comprising: (i) a mixture comprising two or more phosphites and/or phosphates; (ii) one or more thioester compounds; (iii) one or more zinc dihydrocarbyl dithiophosphate compounds; and (iv) one or more oil-soluble or dispersible molybdenum-containing compounds. Such a transmission fluid may be used for controlling and/or reducing wear, e.g., in a manual transmission.

Disclosed is a method for maintaining emulsion stability in a hybrid engine. The method involves lubricating and operating the hybrid engine with a lubricating oil composition having a major amount of an oil of lubricating viscosity; minor amount of a magnesium containing detergent, and a minor amount of a borated dispersant.

Disclosed is a method for maintaining emulsion stability in a hybrid engine. The method involves lubricating and operating the hybrid engine with a lubricating oil composition having a major amount of an oil of lubricating viscosity; minor amount of a magnesium containing detergent, and a minor amount of a borated dispersant.