Patent ID: 7410935

Claim:
An gear additive composition, comprising: (a) a base oil component; and (b) a friction modifier mixture including: (i) at least one alkyl phosphonic acid diester of the formula: wherein R 1 is a hydrocarbyl group containing from about 8 to about 24 carbon atoms, R 2 and R 3 are independently selected from a hydrocarbyl group containing from about 1 to about 8 carbon atoms; (ii) at least one alkyl phosphonic acid monoester of the formula wherein R 4 is a hydrocarbyl group containing from about 8 to about 24 carbon atoms, R 5 is selected from hydrogen and a hydrocarbyl group containing from about 1 to about 8 carbon atoms; and (iii) at least one amine salt of a partial ester of phosphoric acid represented by the formula wherein each of R 6 and R 8 is, independently, a hydrocarbyl group, and R 7 is hydrogen or a hydrocarbyl group, and wherein the ratio of (i) to (ii) ranges from about 3 to about 5.5.