BACKGROUND OF THE INVENTION [0002] Efforts to improve upon the performance of natural mineral oil based lubricants by the synthesis of oligomeric hydrocarbon fluids have been the subject of important research and development in the petroleum industry for at least fifty years and have led to the relatively recent market introduction of a number of synthetic lubricants. In terms of lubricant property improvement, the thrust of the industrial research effort on synthetic lubricants has been toward fluids exhibiting useful viscosities over a wide range of temperature, i. e. , improved viscosity index, while also showing lubricity, thermal and oxidative stability and pour point equal to or better than mineral oil.

[0003] The viscosity-temperature relationship of a lubricating oil is one of the critical criteria which must be considered when selecting a lubricant for a particular application. The mineral oils commonly used as a base for single and multigraded lubricants exhibit a relatively large change in viscosity with a change in temperature. Fluids exhibiting such a relatively large change in viscosity with temperature are said to have a low viscosity index. Viscosity Index (VI) is an empirical number which indicates the rate of change in the viscosity of an oil within a given temperature range. A high VI oil, for example, will thin out at elevated temperatures slower than a low VI oil. The advantage of VI rating is that it capsulizes the effects of temperature as a single number. The viscosity index of a common paraffinic mineral oil is usually given a value of about 100. Viscosity

index is determined according to ASTM Method D 2270-93 [1998] wherein the VI is related to kinematic viscosities measured at 40°C and 100°C using ASTM Method D 445-01.

[0004] The American Petroleum Institute defines five groups of base stocks.

Groups I, II and III are mineral oils classified by the amount of saturates and sulfur they contain and by their viscosity indices. Group I base stocks are solvent refined mineral oils. They contain the most saturates and sulfur and have the lowest viscosity indices. They define the bottom tier of lubricant performance.

Group I stocks are the least expensive to produce, and they currently account for about 75 percent of all base stocks. These comprise the bulk of the"conventional" base stocks.

[0005] Groups II and III are the High Viscosity Index and Very High Viscosity Index base stocks. They are hydroprocessed mineral oils. The Group III oils contain less saturates and sulfur than the Group II oils and have higher viscosity indices than the Group II oils do. Groups II and III stocks perform better than the Group I base stocks do, particularly in measures of thermal and oxidative stability.

Isodewaxed oils also belong to Groups II and III. Isodewaxing rids these mineral oils of a significant portion of their waxes, which improves their cold temperature performance greatly. Groups II and III stocks are more expensive to produce than Group I stocks are, and account for about 20 percent of all base stocks.

[0006] Group II and III stocks may be"conventional"or"unconventional." Generally, "unconventional"base stocks are mineral oils with unusually high viscosity indices and unusually low volatilities. Group II and III solvent refined mineral base stocks are"conventional. "Compared to Group I solvent refined oils, hydroprocessed Group II and III oils offer lower volatility, and when properly additized, greater thermal and oxidative stability and lower pour points.

[0007] Group IV consists of polyalphaolefins. Group IV base stocks offer superior volatility, thermal stability, oxidative stability and pour point

characteristics to those of the Group II and III oils with less reliance on additives.

Currently, Group IV stocks, the PAOs, make up about 3 percent of the base oil market. Group V includes all other base stocks not included in Groups I, II, III and IV. Esters are Group V base stocks.

[0008] Polyalphaolefins ("PAOs") comprise a class of hydrocarbons manufactured by the catalytic oligomerization (polymerization to low-molecular- weight products) of linear a-olefins typically ranging from 1-octene to 1- dodecene, with 1-decene being a preferred material, although polymers of lower olefins such as ethylene and propylene may also be used, including copolymers of ethylene with higher olefins, as described in U. S. Patent 4,956, 122 and the patents referred to therein. PAO products have achieved importance in the lubricating oil market.

[0009] The PAO products typically produced may be obtained with a wide range of viscosities varying from highly mobile fluids of low-viscosity, about 2 cSt. , at 100°C to higher molecular weight, viscous materials which have viscosities exceeding 100 cSt. at 100°C. [Note: PAOs are commonly classified according to their approximate kinematic viscosity (KV) at 100° C. The kinematic viscosity of liquid is determined by measuring the time for a volume of liquid to flow a given distance under gravity. Dynamic viscosity can then be obtained by multiplying the measured kinematic viscosity by the density of the liquid. The units for kinematic viscosity are 1 m2/s, commonly converted to cSt. or centistokes (lcSt. =10-6 m2/s) with 1 cSt. being the viscosity of water at 0°C.] [0010] PAOs may be produced by the polymerization of olefin feed in the presence of a catalyst such as A1C13, BF3, or BF3 complexes. Processes for the production of PAOs are disclosed, for example, in the following patents: U. S.

Patents 3,149, 178; 3, 382, 291; 3,742, 082; 3,769, 363; 3,780, 128; 4,172, 855 and 4,956, 122. PAOs are also discussed in Lubrication Fundamentals, J. G. PAO Wills, Marcel Dekker Inc. , (New York, 1980). Subsequent to polymerization, the PAO lubricant range products are hydrogenated in order to reduce the residual

unsaturation. In the course of this reaction, the amount of unsaturation is generally reduced by greater than 90%.

[0011] Hydrocarbons generally, and in particular synthetic PAOs, have found wide acceptability and commercial success in the lubricant field for their superiority to mineral based lubricants. In terms of lubricant property improvement, industrial research efforts on synthetic lubricants has led to PAO fluids exhibiting useful viscosities over a wide range of temperature, i. e., improved viscosity index, while also showing lubricity, thermal and oxidative stability and pour point equal to or better than mineral oil. These relatively new synthetic lubricants lower mechanical friction, enhancing mechanical efficiency over the full spectrum of mechanical loads and do so over a wider range of operating conditions than mineral oil.

[0012] In accordance with customary practice in the lubricant arts, PAOs have been blended with a variety of additives such as functional chemicals, oligomers and polymers and other synthetic and mineral oil based lubricants to confer or improve upon lubricant properties necessary for applications, such as engine lubricants, hydraulic fluids, gear lubricants, etc. Blends and their additive components are described in Kirk-Othmer Encyclopedia of Chemical Technology, fourth edition, volume 15, pages 463-517.

[0013] A particular goal in the formulation of blends is the enhancement of viscosity index by the addition of VI improvers which are typically high molecular weight synthetic organic molecules. Such additives are commonly produced from polyisobutylenes, polymethacrylates and polyalkylstyrenes, and used in the molecular weight range of about 45,000 to about 1,700, 000. While effective in improving viscosity index, these VI improvers have been found to be deficient because the very property of high molecular weight that makes them useful as VI improvers also confers upon the blend a vulnerability in shear stability during actual applications. Temporary shear results from the non- Newtonian viscometrics associated with solutions of high molecular weight

polymers and is caused by an alignment of the polymer chains with the shear field under high shear rates with a resultant decrease in viscosity. The decreased viscosity reduces the wear protection associated with viscous oils. (Newtonian fluids, in contrast, maintain their viscosity regardless of shear rate. ) This deficiency in shear stability dramatically reduces the range of useful applications for many VI improver additives. Accordingly, workers in the lubricant arts continue to search for better lubricant blends with high viscosity indices.

[0014] Current market conditions are extremely favorable for lubricant compositions which provide lower operating temperatures, increased operating efficiency, and increased hardware durability. With the advent of longer axle and transmission oil change intervals (ca 250,000 to 500,000 miles), durability is clearly at issue as well. Accordingly, the present invention meets these needs by allowing for the preparation of multigraded automotive gear lubricants, and lubricating fluids, which out perform prior art formulations and have none, or a greatly decreased amount of, the deficiencies found in the currently commercially available lubricants.

SUMMARY OF THE INVENTION [0015] The present invention comprises novel lubricating compositions, automotive gear lubricating compositions, and fluids useful in the preparation of finished automotive gear lubricants. The novel lubricating compositions of the present invention comprise a high viscosity fluid blended with a lower viscosity fluid, wherein the final blend has a viscosity index greater than or equal to 175. In another embodiment, the novel lubricating compositions of the present invention comprise a major amount of a blend of a high viscosity fluid blended with a lower viscosity fluid, wherein the final blend has a viscosity index greater than or equal to 175. The blend of the high viscosity fluid and the lower viscosity fluid is generally in a major amount when present in an amount about 70wt. % or greater by weight of the total composition, preferably about 90% or greater by weight of the total composition. Preferably, the high viscosity fluid comprises a

polyalphaolefin and/or the lower viscosity fluid comprises a synthetic hydrocarbon. In another embodiment, the novel lubricating compositions of the present invention further comprise one or more of an ester, mineral oil and/or hydroprocessed mineral oil.

[0016] In another embodiment, the novel lubricating compositions of the present invention comprise finished gear oil.

[0017] In another embodiment, the present invention comprises a method of preparing lubricating compositions, having the properties discussed herein, comprising blending a high viscosity fluid with a lower viscosity fluid, wherein the final blend has a viscosity index greater than or equal to 175. The method may also further comprise the addition of one or more of an ester, mineral oil and/or hydroprocessed mineral oil, optionally in the percentages by weight discussed herein.

[0018] In another embodiment, the novel lubricating compositions of the present invention comprise: a high viscosity fluid, said high viscosity fluid having a viscosity of greater than or equal to 40 cSt. at 100°C and less than or equal to 3,000 cSt. at 100°C, blended with a lower viscosity fluid, said lower viscosity fluid having a viscosity of less than or equal to 40 cSt. at 100°C, wherein the final blend of said high viscosity fluid and said lower viscosity fluid has a viscosity index greater than or equal to 175.

[0019] In another embodiment, the present invention comprises an automotive gear lubricating composition comprising: a high viscosity fluid, said high viscosity fluid having a viscosity of greater than or equal to 40 cSt. at 100°C and less than or equal to 3,000 cSt. at 100°C, blended with a lower viscosity fluid, said lower viscosity fluid having a viscosity of less than or equal to 40 cSt. at 100°C, wherein the final blend of said high viscosity fluid and said lower viscosity fluid has a viscosity index greater than or equal to 175.

[0020] In another embodiment, the present invention comprises an automotive gear lubricating composition comprising a blend of components (A) and (B), wherein: component (A) comprises a high viscosity fluid, said high viscosity fluid having (i) a viscosity of greater than or equal to 40 cSt. at 100°C and less than or equal to 3,000 cSt. at 100°C and, (ii) a viscosity index greater than or equal to 180; and component (B) comprises a lower viscosity fluid, said lower viscosity fluid having a viscosity of less than or equal to 40 cSt. at 100°C ; wherein the final blend of components (A) and (B) has a viscosity index greater than or equal to 175.

[0021] In another embodiment, the present invention comprises a method of preparing a lubricating composition comprising blending a high viscosity fluid, said high viscosity fluid having a viscosity of greater than or equal to 40 cSt. at 100°C and less than or equal to 3,000 cSt. at 100°C, blended with a lower viscosity fluid, said lower viscosity fluid having a viscosity of less than or equal to 40 cSt. at 100°C, wherein the final blend of said high viscosity fluid and said lower viscosity fluid has a viscosity index greater than or equal to 175.

[0022] In another embodiment, the present invention comprises an automotive gear lubricating composition comprising: a major amount of a blend of a high viscosity fluid blended with a lower viscosity fluid, said high viscosity fluid having a viscosity of greater than or equal to 40 cSt. at 100°C and less than or equal to 3,000 cSt. at 100°C, said lower viscosity fluid having a viscosity of less than or equal to 40 cSt. at 100°C, wherein the final blend of said high viscosity fluid and said lower viscosity fluid has a viscosity index greater than or equal to 175.

[0023] In another embodiment, the present invention comprises an automotive gear lubricating composition comprising: a high viscosity fluid, said high viscosity fluid having a viscosity of greater than or equal to 80 cSt. at 100°C and less than or equal to 300 cSt. at 100°C, blended with a lower viscosity fluid, said

lower viscosity fluid having a viscosity of less than or equal to 6 cSt. at 100°C and greater than or equal to 1.5 cSt. at 100°C, wherein the final blend of said high viscosity fluid and said lower viscosity fluid has a viscosity index greater than or equal to 190.

BRIEF DESCRIPTION OF THE FIGURES [0024] Figure 1 presents graphically test results in accordance with embodiments of the present invention relative to currently available commercial gear oils.

[0025] Figure 2 presents graphically test results in accordance with embodiments of the present invention relative to currently available commercial gear oils.

DESCRIPTION OF THE INVENTION [0026] The present invention comprises novel lubricating compositions useful in the preparation of finished gear lubricants and automotive gear lubricants. The novel lubricating compositions of the present invention comprise a high viscosity fluid blended with a lower viscosity fluid, wherein the final blend of the high viscosity fluid and the lower viscosity fluid has a viscosity index greater than or equal to 175. In another embodiment, the novel lubricating compositions of the present invention comprise a major amount of a blend of a high viscosity fluid blended with a lower viscosity fluid, wherein the final blend of said high viscosity fluid and said lower viscosity fluid has a viscosity index greater than or equal to 175. (The blend of the high viscosity fluid and the lower viscosity fluid is generally in a major amount when present in an amount about 70% or greater by weight of the total composition, preferably about 90% or greater by weight of the total composition. ) Compositions of the present invention exhibit very high stability to permanent shear and, because of their Newtonian nature, very little, if any, temporary shear thereby maintaining the viscosity required for proper wear protection.

[0027] In another embodiment, the novel lubricating compositions of the present invention comprise: a high viscosity fluid, said high viscosity fluid having a viscosity of greater than or equal to 40 cSt. at 100°C and less than or equal to 3,000 cSt. at 100°C, blended with a lower viscosity fluid, said lower viscosity fluid having a viscosity of less than or equal to 40 cSt. at 100°C, wherein the final blend of said high viscosity fluid and said lower viscosity fluid has a viscosity index greater than or equal to 175.

[0028] In another embodiment of the novel lubricating compositions of the present invention, the high viscosity fluid has a viscosity of greater than or equal to 60 cSt. at 100°C. In another embodiment of the novel lubricating compositions of the present invention, the high viscosity fluid has a viscosity of less than or equal to 1,000 cSt. at 100°C. In another embodiment of the novel lubricating compositions of the present invention, the high viscosity fluid has a viscosity of greater than or equal to 60 cSt. at 100°C and less than or equal to 1,000 cSt. at 100°C.

[0029] In another embodiment of the novel lubricating compositions of the present invention, the high viscosity fluid has a viscosity of greater than or equal to 80 cSt. at 100°C. In another embodiment of the novel lubricating compositions of the present invention, the high viscosity fluid has a viscosity of less than or equal to 300 cSt. at 100°C. In another embodiment of the novel lubricating compositions of the present invention, the high viscosity fluid has a viscosity of greater than or equal to 80 cSt. at 100°C and less than or equal to 300 cSt. at 100°C.

[0030] In another embodiment of the novel lubricating compositions of the present invention, the lower viscosity fluid has a viscosity of less than or equal to 10 cSt. at 100°C. In another embodiment of the novel lubricating compositions of the present invention, the lower viscosity fluid has a viscosity of less than or equal to 6 cSt. at 100°C. In another embodiment of the novel lubricating compositions

of the present invention, the lower viscosity fluid has a viscosity of greater than or equal to 1.5 cSt. at 100°C and less than or equal to 10 cSt. at 100°C. In another embodiment of the novel lubricating compositions of the present invention, the lower viscosity fluid has a viscosity of greater than or equal to 1.5 cSt. at 100°C and less than or equal to 6 cSt. at 100°C.

[0031] In another embodiment of the novel lubricating compositions of the present invention, the viscosity index of the final blend of the high viscosity fluid and the lower viscosity fluid is greater than or equal to 190.

[0032] In another embodiment of the novel lubricating compositions of the present invention, the high viscosity fluid and the lower viscosity fluid comprise base stocks.

[0033] In another embodiment, the novel lubricating compositions of the present invention further comprise an ester. In another embodiment of the novel lubricating compositions of the present invention, the high viscosity fluid comprises a polyalphaolefin. In another embodiment of the novel lubricating compositions of the present invention, the high viscosity fluid and the lower viscosity fluid comprise polyalphaolefins. In another embodiment of the novel lubricating compositions of the present invention, the lower viscosity fluid comprises a synthetic hydrocarbon. In another embodiment, the novel lubricating compositions of the present invention further comprise one or more of an ester, mineral oil and/or hydroprocessed mineral oil.

[0034] In another embodiment of the novel lubricating compositions of the present invention, the high viscosity fluid comprises a polyalphaolefin in an amount of from about 30% to about 60% by weight of the total composition. In another embodiment of the novel lubricating compositions of the present invention, the lower viscosity fluid comprises 0% to about 70% by weight of the total composition of a synthetic hydrocarbon. In another embodiment, the novel lubricating compositions of the present invention further comprise 0% to about

20% by weight of the total composition of an ester. In another embodiment, the novel lubricating compositions of the present invention further comprise 0% to about 20% by weight of the total composition of one or more of an ester, mineral oil and/or hydroprocessed mineral oil.

[0035] In another embodiment, the novel lubricating compositions of the present invention further comprise one or more of : thickeners, antioxidants, inhibitor packages, and/or anti-rust additives; and/or further comprise one or more of : dispersants, detergents, friction modifiers, traction improving additives, demulsifiers, defoamants, chromophores (dyes), and/or haze inhibitors.

[0036] In another embodiment, the novel lubricating compositions of the present invention, comprise a finished gear oil. In another embodiment of the finished gear oil of the present invention, the blend of the high viscosity fluid blended with the lower viscosity fluid comprises a major amount of said finished gear oil.

[0037] In another embodiment, the novel lubricating compositions of the present invention further comprise extreme pressure protection and anti-wear additives.

[0038] In another embodiment, the novel lubricating compositions of the present invention comprises an automatic transmission fluid, manual transmission fluid, transaxle lubricant, gear lubricant, open gear lubricant, enclosed gear lubricant, and/or tractor lubricant.

[0039] In another embodiment, the novel lubricating compositions of the present invention comprises a contact surface comprising at least a portion of an automatic transmission, manual transmission, transaxle, gear, open gear, enclosed gear, and/or tractor.

[0040] In another embodiment, the present invention comprises an automotive gear lubricating composition comprising: a high viscosity fluid, said high viscosity fluid having a viscosity of greater than or equal to 40 cSt. at 100°C and

less than or equal to 3,000 cSt. at 100°C, blended with a lower viscosity fluid, said lower viscosity fluid having a viscosity of less than or equal to 40 cSt. at 100°C, wherein the final blend of said high viscosity fluid and said lower viscosity fluid has a viscosity index greater than or equal to 175.

[0041] In another embodiment of the novel automotive gear lubricating compositions of the present invention, the high viscosity fluid has a viscosity of greater than or equal to 60 cSt. at 100°C. In another embodiment of the novel automotive gear lubricating compositions of the present invention, the high viscosity fluid has a viscosity of less than or equal to 1,000 cSt. at 100°C. In another embodiment of the novel automotive gear lubricating compositions of the present invention, the high viscosity fluid has a viscosity of greater than or equal to 60 cSt. at 100°C and less than or equal to 1,000 cSt. at 100°C.

[0042] In another embodiment of the novel automotive gear lubricating compositions of the present invention, the high viscosity fluid has a viscosity of greater than or equal to 80 cSt. at 100°C. In another embodiment of the novel automotive gear lubricating compositions of the present invention, the high viscosity fluid has a viscosity of less than or equal to 300 cSt. at 100°C. In another embodiment of the novel automotive gear lubricating compositions of the present invention, the high viscosity fluid has a viscosity of greater than or equal to 80 cSt. at 100°C and less than or equal to 300 cSt. at 100°C.

[0043] In another embodiment of the novel automotive gear lubricating compositions of the present invention, the lower viscosity fluid has a viscosity of less than or equal to 10 cSt. at 100°C. In another embodiment of the novel automotive gear lubricating compositions of the present invention, the lower viscosity fluid has a viscosity of less than or equal to 6 cSt. at 100°C. In another embodiment of the novel automotive gear lubricating compositions of the present invention, the lower viscosity fluid has a viscosity of greater than or equal to 1.5 cSt. at 100°C and less than or equal to 10 cSt. at 100°C. In another embodiment

of the novel automotive gear lubricating compositions of the present invention, the lower viscosity fluid has a viscosity of greater than or equal to 1.5 cSt. at 100°C and less than or equal to 6 cSt. at 100°C.

[0044] In another embodiment of the novel automotive gear lubricating compositions of the present invention, the viscosity index of the final blend of the high viscosity fluid and the lower viscosity fluid is greater than or equal to 190.

In another embodiment of the novel automotive gear lubricating compositions of the present invention, the high viscosity fluid and the lower viscosity fluid comprise base stocks.

[0045] In another embodiment, the novel automotive gear lubricating compositions of the present invention further comprise an ester. In another embodiment of the novel automotive gear lubricating compositions of the present invention, the high viscosity fluid comprises a polyalphaolefin. In another embodiment of the novel automotive gear lubricating compositions of the present invention, the high viscosity fluid and the lower viscosity fluid comprise polyalphaolefins. In another embodiment of the novel automotive gear lubricating compositions of the present invention, the lower viscosity fluid comprises a synthetic hydrocarbon. In another embodiment, the novel automotive gear lubricating compositions of the present invention further comprise one or more of an ester, mineral oil and/or hydroprocessed mineral oil.

[0046] In another embodiment of the novel automotive gear lubricating compositions of the present invention, the high viscosity fluid comprises a polyalphaolefin in an amount of from about 30% to about 60% by weight of the total composition. In another embodiment of the novel automotive gear lubricating compositions of the present invention, the lower viscosity fluid comprises 0% to about 70% by weight of the total composition of a synthetic hydrocarbon. In another embodiment, the novel automotive gear lubricating compositions of the present invention further comprise 0% to about 20% by weight of the total composition of an ester. In another embodiment, the novel

automotive gear lubricating compositions of the present invention further comprise 0% to about 20% by weight of the total composition of one or more of an ester, mineral oil and/or hydroprocessed mineral oil.

[0047] In another embodiment, the novel automotive gear lubricating compositions of the present invention further comprise one or more of : thickeners, antioxidants, inhibitor packages, and/or anti-rust additives; and/or further comprise one or more of : dispersants, detergents, friction modifiers, traction improving additives, demulsifiers, defoamants, chromophores (dyes), and/or haze inhibitors.

[0048] In another embodiment, the novel automotive gear lubricating compositions of the present invention comprise a finished gear oil. In another embodiment, of said finished gear oil of the present invention the blend of the high viscosity fluid blended with the lower viscosity fluid comprises a major amount of said finished gear oil.

[0049] In another embodiment, the novel automotive gear lubricating compositions of the present invention further comprise extreme pressure protection and anti-wear additives.

[0050] In another embodiment, the novel automotive gear lubricating compositions of the present invention comprises an automatic transmission fluid, manual transmission fluid, transaxle lubricant, gear lubricant, open gear lubricant, enclosed gear lubricant, and/or tractor lubricant.

[0051] In another embodiment, the novel automotive gear lubricating compositions of the present invention comprises a contact surface comprising at least a portion of an automatic transmission, manual transmission, transaxle, gear, open gear, enclosed gear, and/or tractor.

[0052] In another embodiment, the present invention comprises an automotive gear lubricating composition comprising a blend of components (A) and (B), wherein: component (A) comprises a high viscosity fluid, said high viscosity fluid having (i) a viscosity of greater than or equal to 40 cSt. at 100°C and less than or equal to 3,000 cSt. at 100°C and, (ii) a viscosity index greater than or equal to 180; and component (B) comprises a lower viscosity fluid, said lower viscosity fluid having a viscosity of less than or equal to 40 cSt. at 100°C ; wherein the final blend of components (A) and (B) has a viscosity index greater than or equal to 175.

[0053] In another embodiment of the novel automotive gear lubricating compositions of the present invention, the final blend of components (A) and (B) has a viscosity index greater than or equal to 190.

[0054] In another embodiment of the novel automotive gear lubricating compositions of the present invention, the viscosity index of component (A) is greater than or equal to 190.

[0055] In another embodiment of the novel automotive gear lubricating compositions of the present invention, component (A) and component (B) comprise base stocks.

[0056] In another embodiment, the novel automotive gear lubricating compositions of the present invention further comprise an ester. In another embodiment, the novel automotive gear lubricating compositions of the present invention further comprise 0% to about 20% by weight of the total composition of an ester.

[0057] In another embodiment of the novel automotive gear lubricating compositions of the present invention, component (A) comprises a polyalphaolefin.

[0058] In another embodiment of the novel automotive gear lubricating compositions of the present invention, components (A) and (B) comprise polyalphaolefins.

[0059] In another embodiment, the novel automotive gear lubricating compositions of the present invention further comprise one or more of an ester, mineral oil and/or hydroprocessed mineral oil. In another embodiment, the novel automotive gear lubricating compositions of the present invention further comprise 0% to about 20% by weight of the total composition of one or more of an ester, mineral oil and/or hydroprocessed mineral oil.

[0060] In another embodiment of the novel automotive gear lubricating compositions of the present invention, component (A) comprises a polyalphaolefin in an amount of from about 30% to about 60% by weight of the total composition.

[0061] In another embodiment, the novel automotive gear lubricating compositions of the present invention further comprise one or more of : thickeners, antioxidants, inhibitor packages, and/or anti-rust additives; and/or further comprise one or more of : dispersants, detergents, friction modifiers, traction improving additives, demulsifiers, defoamants, chromophores (dyes), and/or haze inhibitors.

[0062] In another embodiment, the novel automotive gear lubricating compositions of the present invention comprise a finished gear oil.

[0063] In another embodiment, the novel automotive gear lubricating compositions of the present invention further comprise extreme pressure protection and anti-wear additives.

[0064] In another embodiment, the novel automotive gear lubricating compositions of the present invention comprises an automatic transmission fluid, manual transmission fluid, transaxle lubricant, gear lubricant, open gear lubricant, enclosed gear lubricant, and/or tractor lubricant.

[0065] In another embodiment, the novel automotive gear lubricating compositions of the present invention comprise a contact surface comprising at least a portion of an automatic transmission, manual transmission, transaxle, gear, open gear, enclosed gear, and/or tractor.

[0066] In another embodiment, the present invention comprises a method of preparing a lubricating composition comprising blending a high viscosity fluid, said high viscosity fluid having a viscosity of greater than or equal to 40 cSt. at 100°C and less than or equal to 3,000 cSt. at 100°C, with a lower viscosity fluid, said lower viscosity fluid having a viscosity of less than or equal to 40 cSt. at 100°C, wherein the final blend of said high viscosity fluid and said lower viscosity fluid has a viscosity index greater than or equal to 175.

[0067] In another embodiment of the method of preparing a lubricating composition of the present invention, the high viscosity fluid has a viscosity index of 180 or greater.

[0068] In another embodiment of the method of preparing a lubricating composition of the present invention, the final blend of said high viscosity fluid and said lower viscosity fluid has a viscosity index greater than or equal to 190.

[0069] In another embodiment of the method of preparing a lubricating composition of the present invention, the high viscosity fluid and the lower viscosity fluid comprise base stocks.

[0070] In another embodiment of the method of preparing a lubricating composition of the present invention, the blend of the high viscosity fluid blended

with the lower viscosity fluid comprises a major amount of the lubricating composition.

[0071] In another embodiment of the method of preparing a lubricating composition of the present invention, the high viscosity fluid comprises a polyalphaolefin.

[0072] In another embodiment of the method of preparing a lubricating composition of the present invention, the lower viscosity fluid comprises a synthetic hydrocarbon.

[0073] In another embodiment, the method of preparing a lubricating composition of the present invention further comprises the step of adding 0% to about 20% by weight of the total composition of an ester.

[0074] In another embodiment, the method of preparing a lubricating composition of the present invention further comprises the step of adding 0% to about 20% by weight of the total composition of one or more of an ester, mineral oil and/or hydroprocessed mineral oil.

[0075] In another embodiment, the method of preparing a lubricating composition of the present invention further comprises the step of adding one or more of : thickeners, antioxidants, inhibitor packages, and/or anti-rust additives; and/or further comprises the step of adding one or more of : dispersants, detergents, friction modifiers, traction improving additives, demulsifiers, defoamants, chromophores (dyes), and/or haze inhibitors.

[0076] In another embodiment, the method of preparing a lubricating composition of the present invention further comprises the step of adding extreme pressure protection and anti-wear additives.'

[0077] In another embodiment, the product of the method of preparing a lubricating composition of the present invention comprises an automatic transmission fluid, manual transmission fluid, transaxle lubricant, gear lubricant, open gear lubricant, enclosed gear lubricant, and/or tractor lubricant.

[0078] In another embodiment, the product of the method of preparing a lubricating composition of the present invention comprises a contact surface comprising at least a portion of an automatic transmission, manual transmission, transaxle, gear, open gear, enclosed gear, and/or tractor.

[0079] In another embodiment, the present invention comprises the product of the aforementioned method of preparing a lubricating composition.

[0080] In another embodiment, the present invention comprises an automotive gear lubricating composition comprising: a major amount of a blend of a high viscosity fluid blended with a lower viscosity fluid, said high viscosity fluid having a viscosity of greater than or equal to 40 cSt. at 100°C and less than or equal to 3,000 cSt. at 100°C, said lower viscosity fluid having a viscosity of less than or equal to 40 cSt. at 100°C, wherein the final blend of said high viscosity fluid and said lower viscosity fluid has a viscosity index greater than or equal to 175.

[0081] In another embodiment of the novel automotive gear lubricating composition of the present invention comprising a major amount of a blend of a high viscosity fluid blended with a lower viscosity fluid, said high viscosity fluid and said lower viscosity fluid comprise base stocks.

[0082] In another embodiment, the present invention comprises an automotive gear lubricating composition comprising: a high viscosity fluid, said high viscosity fluid having a viscosity of greater than or equal to 80 cSt. at 100°C and less than or equal to 300 cSt. at 100°C, blended with a lower viscosity fluid, said

lower viscosity fluid having a viscosity of less than or equal to 6 cSt. at 100°C and greater than or equal to 1.5 cSt. at 100°C, wherein the final blend of said high viscosity fluid and said lower viscosity fluid has a viscosity index greater than or equal to 190.

[0083] A preferred embodiment of the present invention comprises a high viscosity fluid, said high viscosity fluid having a viscosity of greater than or equal to 40 cSt. at 100°C and less than or equal to 3,000 cSt. at 100°C, more preferably greater than or equal to 60 cSt. at 100°C and less than or equal to 1,000 cSt. at 100°C, most preferably greater than or equal to 80 cSt. at 100°C and less than or equal to 300 cSt. at 100°C, blended with a lower viscosity fluid, the lower viscosity fluid having a viscosity of less than or equal to 40 cSt. at 100°C, more preferably less than or equal to 10 cSt. at 100°C and greater than or equal to 1.5 cSt. at 100°C, most preferably less than or equal to 6 cSt. at 100°C and greater than or equal to 1.5 cSt. at 100°C, wherein the final blend of the high viscosity fluid and the lower viscosity fluid has a viscosity index greater than or equal to 175, more preferably greater than or equal to 190.

[0084] In a preferred embodiment according to the present invention, the novel automotive gear lubricating compositions comprise: (i) a major amount of a blend (about 70% or greater by weight of the total composition, preferably about 90% or greater) of a high viscosity fluid, said high viscosity fluid having a viscosity of greater than or equal to 40 cSt. at 100°C and less than or equal to 3,000 cSt. at 100°C, blended with a lower viscosity fluid, said lower viscosity fluid having a viscosity of less thaOn or equal to 40 cSt. at 100°C, wherein the final blend of the high viscosity fluild and the lower viscosity fluid has a viscosity index greater than or equal to 175, more preferably greater than or equal to 190 ; and (ii) a minor amount of extreme pressure protection and anti-wear additives.

FLUIDS [0085] High viscosity fluids suitable for the present invention are fluids having a viscosity of greater than or equal to 40 cSt. at 100°C and less than or equal to 3,000 cSt. at 100°C, preferably greater than or equal to 60 cSt. at 100°C and less than or equal to 1,000 cSt. at 100°C, more preferably greater than or equal to 80 cSt. at 100°C and less than or equal to 300 cSt. at 100°C. Lower viscosity fluids suitable for the present invention are fluids having a viscosity of less than or equal to 40 cSt. at 100°C, preferably less than or equal to 10 cSt. at 100°C and greater than or equal to 1.5 cSt. at 100°C, more preferably less than or equal to 6 cSt. at 100°C and greater than or equal to 1.5 cSt. at 100°C. Examples of suitable high viscosity and lower viscosity fluids are discussed hereafter.

[0086] Lower viscosity fluids suitable for the present invention may be synthetic, or of mineral oil, origin although the synthetic materials are preferred.

Suitable mineral oil stocks are characterized by a predominantly saturated (paraffinic) composition, relative freedom from sulfur and a high viscosity index (ASTM D 2270), greater than 110. Saturates (ASTM D 2007) are at least 90 weight percent and the controlled sulfur content is not more than 0.03 weight percent (ASTM D 2622, D 4294, D 4927, D 3120). Lower viscosity fluids of mineral oil origin include the hydroprocessed stocks, especially hydrotreated and catalytically hydrodewaxed distillate stocks, catalytically hydrodewaxed raffinates, hydrocracked and hydroisomerized petroleum waxes, including the lubricating oils referred to as XHVI oils, as well as other oils of mineral origin generally classified as API Group III base stocks. Exemplary streams of mineral origin which may be converted into suitable high quality base stocks by hydroprocessing techniques include waxy distillate stocks such as gas oils, slack waxes, deoiled waxes and microcrystalline waxes, and fuels hydrocracker bottoms fractions. Processes for the hydroisomerization of petroleum waxes and other feeds to produce high quality lube stocks are described in U. S. Patents 5, 885, 438; 5,643, 440; 5,358, 628; 5,302, 279; 5,288, 395; 5,275, 719; 5,264, 116 and 5,110, 445.

The production of very high-quality lubricant base stocks of high viscosity index from fuels hydrocracker bottoms is described in U. S. Patent 5,468, 368.

[0087] Preferred Group V hydrocarbon components suitable for the present invention also include the oils of lubricating viscosity which are hydrocarbon substituted aromatic compounds, such as the long chain alkyl substituted aromatics, including the alkylated naphthalenes, alkylated benzenes, alkylated diphenyl compounds and alkylated diphenyl methanes.

SYNTHETIC HYDROCARBONS [0088] Synthetic lower viscosity fluids suitable for the present invention include the polyalphaolefins (PAOs) and the synthetic oils from the hydrocracking or hydroisomerization of Fischer Tropsch high boiling fractions including waxes.

These are both stocks comprised of saturates with low impurity levels consistent with their synthetic origin. The hydroisomerized Fischer Tropsch waxes are highly suitable base stocks, comprising saturated components of iso-paraffinic character (resulting from the isomerization of the predominantly n-paraffins of the Fischer Tropsch waxes) which give a good blend of high viscosity index and low pour point. Processes for the hydroisomerization of Fischer Tropsch waxes are described in U. S. Patents 5,362, 378; 5,565, 086; 5,246, 566 and 5,135, 638, as well as in EP 710710, EP 321302 and EP 321304.

POLYALPHAOLEFINS ("PAOs") [0089] Polyalphaolefins suitable for the present invention, as either lower viscosity or high viscosity fluids depending on their specific properties, include known PAO materials which typically comprise relatively low molecular weight hydrogenated polymers or oligomers of alphaolefins which include but are not limited to C2 to about C32 alphaolefins with the C8 to about C16 alphaolefins, such as 1-octene, 1-decene, 1-dodecene and the like being preferred. The preferred polyalphaolefins are poly-1-octene, poly-1-decene, and poly-1-dodecene, although

the dimers of higher olefins in the range of Cl4 to Cis provide low viscosity base stocks.

[0090] PAO fluids suitable for the present invention, as either lower viscosity or high viscosity fluids depending on their specific properties, may be conveniently made by the polymerization of an alphaolefin in the presence of a polymerization catalyst such as the Friedel-Crafts catalysts including, for example, aluminum trichloride, boron trifluoride or complexes of boron trifluoride with water, alcohols such as ethanol, propanol or butanol, carboxylic acids or esters such as ethyl acetate or ethyl propionate. For example, the methods disclosed by U. S.

Patents 4,149, 178 or 3,382, 291 may be conveniently used herein. Other descriptions of PAO synthesis are found in the following U. S. Patents: 3,742, 082 (Brennan); 3,769, 363 (Brennan); 3,876, 720 (Heilman); 4,239, 930 (Allphin); 4,367, 352 (Watts); 4,413, 156 (Watts); 4,434, 408 (Larkin); 4,910, 355 (Shubkin); 4,956, 122 (Watts); and 5,068, 487 (Theriot).

[0091] High viscosity PAOs suitable for the present invention may be prepared by the action of a reduced chromium catalyst with the alphaolefin, such PAOs are described in U. S. Patents 4,827, 073 (Wu); 4,827, 064 (Wu); 4,967, 032 (Ho et al. ) ; 4,926, 004 (Pelrine et al. ) ; and, 4,914, 254 (Pelrine). The dimers of the Cl4 to C18 olefins are described in U. S. Patent 4,218, 330. Commercially available high viscosity PAOs include SuperSyn 2150, SuperSyrm 2300, SuperSyn 21000, SyperSyn 23000, (ExxonMobil Chemical Company).

ESTERS [0092] Esters suitable for the present invention include the esters of mono and polybasic acids with monoalkanols (simple esters) or with mixtures of mono and polyalkanols (complex esters), and the polyol esters of monocarboxylic acids (simple esters), or mixtures of mono and polycarboxylic acids (complex esters).

Esters of the mono/polybasic type include, for example, the esters of monocarboxylic acids such as heptanoic acid, and dicarboxylic acids such as

phthalic acid, succinic acid, alkyl succinic acid, alkenyl succinic acid, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl malonic acid, alkenyl malonic acid, etc. , with a variety of alcohols such as butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, or mixtures thereof with polyalkanols, etc. Specific examples of these types of esters include nonyl heptanoate, dibutyl adipate, di (2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, dibutyl-TMP- adipate, etc. Commercially available examples include Esters MI 1, A32, A51 and C3211 esters from ExxonMobil Chemical Company.

[0093] Also suitable for the present invention are esters, such as those obtained by reacting one or more polyhydric alcohols, preferably the hindered polyols such as the neopentyl polyols, e. g, . neopentyl glycol, trimethylol ethane, 2-methyl-2- propyl-1, 3-propanediol, trimethylol propane, trimethylol butane, pentaerythritol and dipentaerythritol with monocarboxylic acids containing at least 4 carbons, normally the 5 to C30 acids such as saturated straight chain fatty acids including caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachic acid, and behenic acid, or the corresponding branched chain fatty acids or unsaturated fatty acids such as oleic acid, or mixtures thereof, with polycarboxylic acids. Commercially available examples include Esters NP341, NP471, and NP3150 esters from ExxonMobil Chemical Company.

EXTREME PRESSURE PROTECTION AND ANTI-WEAR ADDITIVES [0094] In another embodiment, the novel lubricating compositions of the present invention further comprise extreme pressure protection and anti-wear additives.

For example, mixtures of sulfur, phosphorus and/or boron-containing compounds may be included as additives, such as mixtures of Mobilad C-100, MobiladTM C-175 (sulfur) ; MobiladTM C-420, Mobilad C-421, Mobilad C-423 (phosphorus); and/or Mobiladrm C-200 (boron) (ExxonMobil Chemical Company). Lubricants containing these combinations have improved properties

such as those relating to odor, yellow metal protection, thermal stability wear, scuffing, oxidation, surface fatigue, seal compatibility, corrosion resistance, and thermal durability. Other extreme pressure protection and anti-wear additives known in the art may also be used.

OTHER COMPONENTS [0095] Other components which may be included in the novel lubricating compositions of the present invention include, but are not limited to, thickeners, antioxidants, inhibitor packages and/or anti-rust additives. Additionally, other conventional additives may be included in the novel compositions of the present invention as necessary for particular service requirements, for example, dispersants, detergents, friction modifiers, traction improving additives, demulsifiers, defoamants, chromophores (dyes), and/or haze inhibitors, according to application, all of which may be blended according to conventional methods using commercially available materials.

[0096] The viscosity of the lubricating compositions of the present invention may be brought to a desired grade by the use of polymeric thickeners. Suitable thickeners that may be used in the present invention include the polyisobutylenes, as well as ethylene-propylene polymers, polymethacrylates and various diene block polymers and copolymers, polyolefins and polyalkylstyrenes. These components may be blended according to commercial market requirement, equipment builder specifications to produce products of the final desired viscosity grade.

[0097] Typical commercially available thickeners also appropriate for use in lubricating compositions of the present invention include polyisobutylenes, polymerized and co-polymerized alkyl methacrylates, and mixed esters of styrene maleic anhydride interpolymers reacted with nitrogen containing compounds, for example, the ShellvisTM products (in particular, Shellvis Tm 40, Shellvis 50, Shellvis 90, Shellvis 200, ShellvisTM 260 and ShellvisTM 300) by Infineum

International Ltd., AcryloidTM1263 and 1265 by Rohm and Haas, Viscoplex 5151 and 5089 by Rohm-GmbH, and LubrizolTM 3702 and 3715 by Lubrizol Corp.

[0098] Oxidation stability may be enhanced in the lubricating compositions of the present invention by the use of antioxidants and for this purpose a wide range of commercially available materials is suitable. The most common types of antioxidants suitable for use in the present invention are the phenolic antioxidants, the amine type antioxidants, the alkyl aromatic sulfides, phosphorus compounds such as the phosphites and phosphonic acid esters and the sulfur-phosphorus compounds such as the dithiophosphates and other types such as the dialkyl dithiocarbamates, e. g. , methylene bis (di-n-butyl) dithiocarbamate. They may be used individually by type or in combination with one another. Mixtures of different types of phenols or amines are particularly useful. Normally, the total amount of antioxidant will not exceed 10% by weight of the total composition and preferably will be less, for example below 5% by weight of the total composition.

Usually, from 0.5 to 2% by weight of the total composition of an antioxidant is suitable, although for certain applications more may be used if desired.

[0099] An inhibitor package may be used to provide the desired balance of anti- wear and anti-rust/anti-corrosion properties in the lubricating compositions of the present invention. Suitable inhibitor packages include those comprising a substituted benzotriazoleamine phosphate adduct and a tri-substituted phosphate, especially a triaryl phosphate such as cresyl diphenylphosphate, a known material which is commercially available. This component is typically present in minor amounts up to 5% by weight of the composition. Normally less than 3% by weight of the total composition (e. g. , from 0.5 to 2%) is adequate to provide the desired anti-wear performance.

[0100] Also suitable for use in the lubricating compositions of the present invention are inhibitor packages comprising an adduct of benzotriazole or a substituted benzotriazole with an amine phosphate adduct which also provides

antiwear and antioxidation performance. Certain multifunctional adducts of this kind (with aromatic amines) are described in U. S. Patent 4,511, 481 to which reference is made for a description of these adducts together with the method by which they may be prepared.

[0101] Anti-rust additives suitable for use in the present invention include metal deactivators which are commercially available and typically include, for example, the N, N-disubstituted aminomethyl-1, 2,4-triazoles, and the N, N-disubstituted amino methyl-benzotriazoles, the succinimide derivatives such as the higher alkyl substituted amides of dodecylene succinic acid, which are also commercially available, the higher alkyl substituted amides of dodecenyl succinic acid, such as the tetrapropenylsuccinic monoesters (commercially available), and imidazoline succinic anhydride derivatives, e. g. , the imidazoline derivatives of tetrapropenyl succinic anhydride. Normally, these additional rust inhibitors will be used in relatively small amounts below 2% by weight of the total composition; although for certain applications amounts up to about 5% may be employed if necessary.

EXAMPLES [0102] The lubricating compositions of the present invention may be prepared using standard commercial lube oil blending facilities consisting of blend tanks and/or inline mixers where heat is used only to facilitate pumping and complete mixing.

[0103] Examples A-H, hereafter, illustrate properties of embodiments of finished gear oils comprising the lubricating compositions of the present invention. The following tables, charts, and attached Figures summarize the benefits that were observed for embodiments of the present invention.

EXAMPLE A Component Description Wt % SAE Viscosity Grade Additive Package A Gear Oil Additive Package 6.00 ExxonMobil SHFTM 23 Lower viscosity hydrocarbon fluid 24. 00 SAE 70W-90 ExxonMobil EsterexTM M11 Lower viscosity ester 20. 00 VI=227 ExxonMobil Supersyn 2150 High viscosity hydrocarbon fluid 49.98 Silicon Defoamant Defoamant 0. 02 EXAMPLE B

Component Description Wt % SAE Viscosity Grade Additive Package B Gear Oil Additive Package 11.55 Additive Component A Antioxidant 0.50 ExxonMobil SHFTM 23 Lower viscosity hydrocarbon fluid 30.43 SAE 70W-85 ExxonMobil EsterexTM M11 Lower viscosity ester 15.00 VI=227 ExxonMobil Supersyn 2150 High viscosity hydrocarbon fluid 43.00 Silicon Defoamant Defoamant 0.02 EXAMPLE C Component Description Wt % SAE Viscosity Grade Additive Package A Gear Oil Additive Package 5.21 ExxonMobil SHY TU 23 Lower viscosity hydrocarbon fluid 25. 00 SAE 75W-90 ExxonMobil SHFTM 41 Lower viscosity hydrocarbon fluid 21.00 VI=199 ExxonMobil Supersyn 2150 High viscosity hydrocarbon fluid 48.77 Silicon Defoamant Defoamant 0. 02 EXAMPLE D Component Description Wt % SAE Viscosity Grade Additive Package A Gear Oil Additive Package 6.00 ExxonMobil SHFTM 23 Lower viscosity hydrocarbon fluid 24.85 SAE 70W-90 ExxonMobil Esters Mil Lower viscosity ester 21.00 VI=216 ExxonMobil SHFTM 1003 High viscosity hydrocarbon fluid 27. 50 ExxonMobil Supersyn 2300 High viscosity hydrocarbon fluid 21.65

EXAMPLE Component Description Wt % SAE Viscosity Grade Additive Package A Gear Oil Additive Package 6. 00 ExxonMobil SHF 23 Lower viscosity hydrocarbon fluid 28. 13 SAE 70W-90 ExxonMobil EsterexTM Mil Lower viscosity ester 20.00 VI=217 ExxonMobil SHFTM 1003 High viscosity hydrocarbon fluid 36.70 ExxonMobil Supersyn 2300 High viscosity hydrocarbon fluid 9. 17 EXAMPLE Component Description Wt % SAE Viscosity Grade Additive Package A Gear Oil Additive Package 6.00 SAE 75W-90 ExxonMobil SHFTM 23 Lower viscosity hydrocarbon fluid 19.00 ExxonMobil Esterex Ml l Lower viscosity ester 20.00 VI=192 ExxonMobil SHFTM 1003 High viscosity hydrocarbon fluid 55. 00 EXAMPLE G Component Description Wt % SAE Viscosity Grade Additive Package A Gear Oil Additive Package 6.00 Mobilad G205TM Friction Modifier 2.00 ExxonMobil SHF 23 Lower viscosity hydrocarbon fluid 18. 00 SAE 75W-90 ExxonMobil Esterex M11 Lower viscosity ester 20.00 VI=190 ExxonMobil SHFTM 1003 High viscosity hydrocarbon fluid 55. 00 Silicon Defoamant Defoamant 0.02

EXAMPLE H Component Description Wt % SAE Viscosity Grade Additive Package A Gear Oil Additive Package 6.00 Additive Comp A Anti-oxidant 0.25 Alkylated aromatic Lower viscosity API Group V 10.00 hydrocarbon fluid (4.8 cSt. at SAE 75W-90 100-C.) ExxonMobil SHY TU 23 Lower viscosity hydrocarbon fluid 25.80 V ExxonMobil Esterex Ml l Lower viscosity ester 10.00 ExxonMobil Supersyn 2150 High viscosity hydrocarbon fluid 47.93 Silicon Defoamant Defoamant 0.02

TESTING [0104] Finished gear oils comprising the lubricating compositions of the present invention possess previously unseen benefits with respect to vehicle fuel economy and hardware durability and demonstrate significantly enhanced lubricant performance. For instance, when finished gear oils comprising the lubricating compositions of the present invention are tested in truck axles, resultant oil sump temperatures are lower than with current commercially available lubricant fluids across a wide range of operating conditions. These lowered axle sump temperatures are a consequence of reduced friction within the drive train. The reduced friction leads directly to efficiency improvements. The lowered sump temperatures have the effect of enhancing hardware durability. Thus, the lubricant temperature reduction seen in the finished gear oils comprising the lubricating compositions of the present invention yields increased fuel efficiency and hardware durability.

[0105] The performance enhancements of the finished gear oils comprising the lubricating compositions of the present invention can be demonstrated using automotive drive axles on laboratory test stands where defined loads are applied to the test axles at constant axle speeds and constant cooling. The test stages are defined to include the range of actual commercial operating conditions of load and speed. Oil sump temperatures can then be measured to demonstrate indirectly the improved efficiency and hardware durability protection in the field. Alternately, the test stand can be instrumented with torque meters to estimate efficiencies more explicitly.

[0106] One such test uses a light truck axle mounted in a"T-bar"type test configuration similar to ASTM D 6121-01 (the L-37 gear durability test), with the exception that in this test, the power source is from a 250 hp electric motor and constant heat removal is provided by air fans directed at the axle carrier. The axle carrier is filled with test oil and then run through stages of torques and rpms.

Each stage is held until the oil sump temperature has stabilized. The temperature

of each stage is recorded along with torque in and torque out readings if the axle is properly instrumented. The test then moves to the next stage until all stages are completed. Table 1 lists the torque and axle speeds that was used to generate the test data described herein.

TABLE 1 Stage Torque RPM Comments (lbf ft.) 1 50 2000 A combination of torque and speed predictive of typical low load applications 2 70 2000 A combination of torque and speed predictive of typical low load applications 3 95 2000 A combination of torque and speed predictive of typical low load applications 4 189 1000 A combination of torque and speed predictive of middle load applications 5 418 500 A combination of torque and speed predictive of high load applications 6 124 2700 A combination of torque and speed predictive of middle load applications 7 189 2730 A combination of torque and speed predictive of middle load applications 8 242 2730 A combination of torque and speed predictive of middle load applications 9 304 2200 A combination of torque and speed predictive of high load applications 10 418 1000 A combination of torque and speed predictive of high load applications

[0107] In order to more clearly see relative sump temperature improvements, the resultant temperature at each stage is compared relative to currently available commercial gear oils and the data displayed as such in Figure 1.

[0108] In Figure 1, the two commercially available SAE 75W-90 factory fill oils (FF#1 and FF#2) show indirectly the efficiency improvements in test stages 1-3 relative to the 75W-140 reference oil (normalized as shown on the horizontal axis). Significant sump temperature increases relative to the reference at high load stages 5,9, and 10, however, indicate possible film thickness loss and subsequent long-term hardware compromise. Examples A and B of the present invention in contrast show even more striking temperature improvements at the

low stages while maintaining fluid film thickness and therefore hardware protection at the high load stages.

[0109] Figure 2 further demonstrates results for additional embodiments of the present invention.

[0110] Consolidating the test information presented in Figures 1 and 2 from the ten stages into three groups and averaging sump temperature improvements further focuses the benefits imparted by the compositions of the present invention.

Table 2 shows the stage consolidation and Table 3 summarizes the test results shown in Figures 1 and 2.

TABLE 2 Consolidation of Stages into Groups Group ID Discussion Stages used Mild test conditions typical of EPA focus for vehicle A 1,2, 3 mileage documentation Increased hardware stress conditions, yet still well B 4,6, 7,8 within equipment design High stress conditions close to or beyond hardware C 5,9, 10 design envelope

TABLE 3 Relative Sump Temperature Averages, (°F) Oil Tested Group A Group B Group C OEM Reference 75W-140 0 0 0 (0 by definition) OEM FF 75W-90#1-3 2 18 OEM FF 75 W-90#2-7 2 31 Example A-16-18 3 Example B-18-17 6 Example D-14-13 0 Example E-19-16 9

[0111] In conclusion, the aforementioned examples of finished gear oils comprising the lubricating compositions of the present invention demonstrate sump temperature improvements over both the reference and other commercial fluids with little or no durability compromise.

[0112] While certain representative embodiments and details have been shown for purposes of illustrating the invention, it should be recognized that these embodiments are merely illustrative of the principles of the present invention.

Since numerous modifications and changes will readily occur to those skilled in the art, the foregoing is not intended to limit the invention to the exact construction and operation shown and described, and all suitable modifications and equivalents falling within the scope of the appended claims are deemed within the present inventive concept.

[0113] The features of the present invention, together with the other objectives of the invention, and along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure.