Oxidation stable gear oil compositions
A gear oil lubricant composition and method of operating a vehicle with the composition. The composition may include a first olefinic lubricant having a viscosity ranging from about 80 centistokes to about 150 centistokes at 100° C. and a second olefinic lubricant having a viscosity ranging from about 2 centistokes to about 15 centistokes at 100° C. A ratio of the first olefinic lubricant to the second olefinic lubricant may range from about 2:1 to about 8:1. Additionally, the composition may include an alkylated naphthalene base oil, a boronated ashless dispersant, at least one hindered phenol antioxidant, at least one alkylated diphenylamine antioxidant, and a gear oil additive package having an active phosphorus content of less than about 700 ppm and an active sulfur content of less than about 3 wt. %. The gear oil lubricant composition may contain less than about 0.1 percent by weight antioxidant composition based on a total weight of the lubricant composition.
1 . A gear oil lubricant composition comprising:
a first olefinic lubricant having a viscosity ranging from about 80 centistokes to about 150 centistokes at 100° C.;
a second olefinic lubricant having a viscosity ranging from about 2 centistokes to about 15 centistokes at 100° C., wherein a ratio of the first olefinic lubricant to the second olefinic lubricant ranges from about 2:1 to about 8:1;
an alkylated naphthalene base oil;
a boronated ashless dispersant;
an antioxidant composition comprising at least one hindered phenol antioxidant and at least one alkylated diphenylamine antioxidant; and
a gear oil additive package having an active phosphorus content of less than about 700 ppm and an active sulfur content of less than about 2.5 wt. %, wherein the gear oil lubricant composition contains less than about 0.1 percent by weight antioxidant composition based on a total lubricant composition.
2 . The gear oil lubricant composition of claim 1 , wherein the gear oil additive package comprises an extreme pressure agent, an antiwear agent, a rust inhibitor, a corrosion inhibitor, a defoamer, and a process oil.
3 . The gear oil lubricant composition of claim 1 , further comprising a seal swelling agent.
4 . The gear oil lubricant composition of claim 1 , wherein the composition contains from about 100 to about 700 ppm active nitrogen atoms.
5 . The gear oil lubricant composition of claim 1 , wherein the ashless dispersant comprises a hydrocarbyl substituted succinimide.
6 . The gear oil lubricant composition of claim 5 , wherein the ashless dispersant comprises a boronated/phosphorylated ashless dispersant.
7 . The gear oil lubricant composition of claim 1 , wherein the first and second olefinic lubricant comprises oligomers of alphaolefins.
8 . A vehicle axle containing the gear oil lubricant of claim 1 .
9 . A heavy duty gear oil lubricant composition comprising:
a first olefinic lubricant having a viscosity ranging from about 80 centistokes to about 150 centistokes at 100° C.;
a second olefinic lubricant having a viscosity ranging from about 2 centistokes to about 15 centistokes at 100° C., wherein a ratio of the first olefinic lubricant to the second olefinic lubricant ranges from about 2:1 to about 8:1;
an alkylated naphthalene base oil;
a boronated ashless dispersant;
an antioxidant composition comprising at least one hindered phenol antioxidant and at least one alkylated diphenylamine antioxidant; and
a conventional gear oil additive package;
wherein the gear oil lubricant composition has a reactive amine content of less than about 100 to about 400 ppm based on an active nitrogen content of the lubricant composition.
10 . The gear oil lubricant composition of claim 9 , wherein the gear oil additive package comprises an extreme pressure agent, an antiwear agent, a rust inhibitor, a corrosion inhibitor, a defoamer, and a process oil.
11 . The gear oil lubricant composition of claim 9 , further comprising a seal swelling agent.
12 . The gear oil lubricant composition of claim 9 , wherein the composition has an active sulfur content ranging from about 1 wt. % to about 3 wt. % and an active phosphorus content ranging from about 250 to about 700 ppm.
13 . The gear oil lubricant composition of claim 9 , wherein the ashless dispersant comprises a hydrocarbyl substituted succinimide.
14 . The gear oil lubricant composition of claim 13 , wherein the ashless dispersant comprises a boronated/phosphorylated ashless dispersant.
15 . The gear oil lubricant composition of claim 9 , wherein the first and second olefinic lubricant comprises oligomers of alphaolefins.
16 . A vehicle axle containing the gear oil lubricant of claim 9 .
17 . A thermally stable gear oil lubricant composition, comprising:
a first olefinic lubricant having a viscosity ranging from about 80 centistokes to about 150 centistokes at 100° C.;
a second olefinic lubricant having a viscosity ranging from about 2 centistokes to about 15 centistokes at 100° C., wherein a ratio of the first olefinic lubricant to the second olefinic lubricant ranges from about 2:1 to about 8:1;
an alkylated naphthalene base oil;
a boronated ashless dispersant;
an antioxidant composition comprising at least one hindered phenol antioxidant and at least one alkylated diphenylamine antioxidant; and
a conventional gear oil additive package;
wherein, with respect to thermal stability, the lubricant composition has a carbon varnish rating of greater than about 7.4 and a sludge rating of greater than about 9.3 after an L60-1 oxidative stability test of about 300 hours.
18 . The gear oil lubricant composition of claim 17 , wherein the lubricant composition has a viscosity rise of less than about 100%.
19 . The gear oil lubricant composition of claim 17 , wherein the gear oil additive package comprises an extreme pressure agent, an antiwear agent, a rust inhibitor, a corrosion inhibitor, a defoamer, and a process oil.
20 . The gear oil lubricant composition of claim 17 , further comprising a seal swelling agent.
21 . The gear oil lubricant composition of claim 17 , wherein the composition has an active sulfur content ranging from about 1 wt. % to about 3 wt. % and an active phosphorus content ranging from about 300 to about 700 ppm.
22 . The gear oil lubricant composition of claim 17 , wherein the ashless dispersant comprises a hydrocarbyl substituted succinimide.
23 . The gear oil lubricant composition of claim 22 , wherein the ashless dispersant comprises a boronated/phosphorylated ashless dispersant.
24 . The gear oil lubricant composition of claim 17 , wherein the first and second olefinic lubricant comprises oligomers of alphaolefins.
25 . A vehicle axle containing the gear oil lubricant of claim 17 .
26 . A method of operating a vehicle containing a drive axle, comprising providing as a lubricant for the drive axle a composition containing:
a first olefinic lubricant having a viscosity ranging from about 80 centistokes to about 150 centistokes at 100° C.;
a second olefinic lubricant having a viscosity ranging from about 2 centistokes to about 15 centistokes at 100° C., wherein a ratio of the first olefinic lubricant to the second olefinic lubricant ranges from about 2:1 to about 8:1;
an alkylated naphthalene base oil;
a boronated ashless dispersant;
an antioxidant composition comprising at least one hindered phenol antioxidant and at least one alkylated diphenylamine antioxidant; and
a conventional gear oil additive package;
wherein the lubricant composition has an oxidation stability in a 300 hour L60-1 oxidative stability test that provides a viscosity increase of less than about 100%, a carbon varnish rating of greater than about 7.4 and a sludge rating of greater than or equal to 9.3.
27 . The method of claim 28 wherein the vehicle is operated in an environment having a temperature of greater than about 40° C.
28 . The method of claim 28 wherein the vehicle is operated for a distance of more than about 30,000 kilometers between lubricant drain intervals.
29 . The method of claim 28 wherein the axle is an axle of a heavy duty truck vehicle.
30 . The method of claim 29 wherein the heavy duty truck vehicle can pull combined loads in excess of 25 metric tons.