Transmission composition

Abstract

There is provided a transmission composition including a lead corrosion reducing effective amount of at least one lead corrosion inhibitor selected from the group consisting of sulfurized alkylphenols; phosphosulfurized hydrocarbons; substituted or unsubstituted thiocarbamates; substituted or unsubstituted thiazoles; substituted or unsubstituted triazoles; substituted or unsubstituted thiadiazoles.

Description

FIELD OF THE DISCLOSURE

The present disclosure relates to a fluid composition comprising at least one lead corrosion inhibitor. The at least one lead corrosion inhibitor provides at least one property chosen from corrosion inhibition, improved wear, improved lubricity, and improved lead compatibility. The transmission fluid composition disclosed herein includes fluids that may be suitable for use in an automatic transmission, dual clutch transmission, continuously variable transmission, and/or a manual transmission.

BACKGROUND OF THE DISCLOSURE

Transmissions can have twenty or more parts that contain lead as part of their materials of construction. For example, most of the plain bearings in the shifting clutches in an automatic transmission contain lead in the form of a copper-lead alloy. When a transmission is in operation the lubricant degrades to form oxidation products and additive decomposition products that are corrosive to lead.

For copper-lead alloy bushings, regardless of the application, there is general agreement that it is a combination of corrosive and mechanical wear that results in equipment failure. The shifting clutch bearing assemblies in, for example, automatic transmissions can experience high loads and speeds that result in boundary lubrication. If either lead or copper is removed from, for example, the bushing matrix, the structure can be undermined and weakened. Once the alloy starts to erode, there can be metal-to-metal contact between the steel backing and the counter surface (input or output shaft). This can result in galling of the steel backing and damage to the counter surface. Generally, insoluble wear debris will be trapped in the filter. However, if the wear debris reduces the fluid flow rate to such a point that the transmission experiences fluid starvation, there can be loss of hydraulic pressure, loss of the critical functions, and catastrophic failure. Thus, for any given metal or alloy, wear can be due to the combined influences of additives, basestocks, temperatures, and the application.

While there are similarities between driveline and crankcase fluid applications, there can be significant differences between the areas. Most newer automatic transmission fluids (ATFs) are not formulated with zinc dialkyldithiophosphates (ZDDPs) which are known to damage the friction material in torque converters and shifting clutches. Moreover, because ATFs are not subjected to acidic blow-by gases they are usually formulated with lower levels of overbased detergents than engine oils, such as from about 0.1% for ATFs and about 1% for engine oils. The differences between driveline and motor oil formulations and applications may result in some differences between their lead corrosion mechanisms.

SUMMARY OF THE DISCLOSURE

According to various embodiments, there is provided a transmission fluid composition comprising a lead corrosion reducing effective amount of at least one lead corrosion inhibitor selected from the group consisting of sulfurized alkylphenols; phosphosulfurized hydrocarbons; substituted or unsubstituted thiocarbamates; substituted or unsubstituted thiazoles; substituted or unsubstituted triazoles; substituted or unsubstituted thiadiazoles; a method for inhibiting lead corrosion of machinery comprising providing to machinery a fluid composition comprising at least one lead corrosion inhibitor selected from the group consisting of sulfurized alkylphenols; phosphosulfurized hydrocarbons; substituted or unsubstituted thiocarbamates; substituted or unsubstituted thiazoles; substituted or unsubstituted triazoles; substituted or unsubstituted thiadiazoles; and a composition comprising at least one lead corrosion inhibitor, wherein the composition meets the standards for an aluminum beaker oxidation test measuring a percent weight loss of a lead coupon.

Additional objects and advantages of the disclosure will be set forth in part in the description which follows, and can be learned by practice of the disclosure. The objects and advantages of the disclosure will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure, as claimed.

DESCRIPTION OF THE DISCLOSURE

In accordance with the present disclosure, there is provided a transmission fluid composition comprising a lead corrosion reducing effective amount of at least one lead corrosion inhibitor.

The disclosed lead corrosion inhibitor can be present in the composition in any desired or effective amount so long as it reduces lead corrosion. In one embodiment, the lead corrosion inhibitor can be present in the composition in an amount ranging from about 0.01% to about 5%, for example from about 0.05% to about 3%, and as a further example from about 0.2% to about 1%, by weight relative to the total weight of the composition.

The lead corrosion inhibitor for use in the disclosed composition can be chosen from sulfurized alkylphenols; phosphosulfurized hydrocarbons; substituted or unsubstituted thiocarbamates; substituted or unsubstituted thiazoles; substituted or unsubstituted triazoles; substituted or unsubstituted thiadiazoles; and combinations and mixtures thereof. In one embodiment, the phosphosulfurized hydrocarbons can be chosen from the reaction product of a phosphorus sulfide with turpentine or methyl oblate.

The substituted or unsubstituted thiocarbamates suitable for use as the lead corrosion inhibitor include, but are not limited to, metal thiocarbamates, such as zinc dioctyidithiocarbamate, and barium diheptylphenyl dithiocarbamate; and ashless dithiocarbamates such as reaction products of a dithiocarbamic acid and an unsaturated acid, ester, anhydride, amide, ether, or imide.

Dithiocarbamates have been known in the art for some time. Examples of various structurally different dithiocarbamates are disclosed in the following patents: U.S. Pat. Nos. 3,407,222; 5,693,598; 4,885,365; 4,125,479; 5,902,776; 3,867,359; 5,686,397; 4,836,942; 4,758,362; 3,509,051; 2,710,872; 5,789,357; 4,927,552; 5,629,272; 3,356,702; 5,840,664; 4,957,643; 4,876,375; 5,759,965; 4,098,705. All patents, patent applications, and articles or publications are incorporated herein by reference for their full disclosure.

Examples of commercially available dithiocarbamates include a methylenebis(dibutyldithiocarbamate); a molybdenum oxysulfide dithiocarbamate; an organo molybdenum dithiocarbamate; a zinc diamyldithiocarbamate; a lead diamyldithiocarbamate; an antimony dialkyldithiocarbamate; and a dithiocarbamate derivative, all obtained from R.T. Vanderbilt Company, Inc.

Non-limiting examples of the substituted or unsubstituted thiazoles, triazoles, and thiadiazoles for use in the disclosed composition include benzotriazole, tolyltriazole, octyltriazole, decyltriazole, dodecyltriazole, 2-mercapto-benzothiazole, 2,5-dimercapto-1,3,4-thiadiazole, 2-mercapto-5-hydrocarbylthio-1,3,4-thiadiazoles, 2-mercapto-5-hydrocarbyldithio-1,3,4-thiadiazoles, 2,5-bis(hydrocarbylthio)-1,3,4-thiadiazoles, and 2,5-bis(hydrocarbyldithio)-1,3,4-thiadiazoles. The hydrocarbyl substituent can be selected from alkyl groups having from about 1 to about 30 carbon atoms, for example heptyl, octyl, nonyl, decyl, undecyl, dodecyl, and cetyl groups, and isomers thereof.

In one embodiment, 1,3,4-thiadiazoles, for example the 2-hydrocarbyldithio-5-mercapto-1,3,4-dithiadiazoles and the 2,5-bis(hydrocarbyldithio)-1,3,4-thiadiazoles, can be used, a number of which are commercially available. In one embodiment, 2-mercapto benzothiazole available from Vanderbilt can be used

The 1,3,4-thiadiazole compounds, or mixtures thereof, contemplated for use in the present disclosure can be readily obtained from commercial sources or can be synthesized from hydrazine and carbon disulfide in a well-known manner. U.S. Pat. Nos. 2,765,289; 2,749,311; 2,760,933; 2,850,453; 2,910,439; 3,663,561; 3,862,798; and 3,840,549 can be referred to for detailed procedures on the preparation of the 1,3,4-thiadiazole compounds contemplated for use in lubricating compositions of the present disclosure.

The disclosed composition can further comprise a detergent, such as at least one overbased alkaline-earth metal phenate. The detergent can be present in the composition in any desired or effective amount, such as, from about 0.01% to about 5%, for example from about 0.04% to about 3%, and as a further example from about 0.2% to about 1% by weight, relative to the total weight of the composition.

Overbased alkaline-earth metal phenates can be defined by the amount of total basicity contained in the product. It has become popular to label a detergent by its TBN (total base number), i.e. a 300 TBN synthetic sulfonate. Base number is defined in terms of the equivalent amount of potassium hydroxide contained in the material. A 300 TBN calcium sulfonate contains base equivalent to 300 milligrams of potassium hydroxide per gram or, more simply, 300 mg KOH/g. Two factors limit the degree of overbasing: oil solubility and filterability.

The overbased alkaline-earth metal phenate useful in the present disclosure should have TBN's of from about 25 to about 350, for example from about 100 to about 250, and as a further example from about 150 to about 250. A detergent with a high TBN can range from about 150 to about 450, for example from about 200 to about 400, and as a further example from about 250 to about 350. A detergent with a low TBN can range from about 25 to about 150, for example from about 50 to about 100, and as a further example from about 75 to about 85. Representative of the commercially available high TBN phenates which can be useful in the present disclosure include: OLOA™ 216S (5.25% calcium, 3.4% sulfur, 145 TBN); OLOA™ 219C (9.60% calcium, 3.4% sulfur, 263 TBN); OLOA™ 246S (2.35% calcium, 2.77% sulfur, 17 TBN); OLOA™ 247Z (12.75% calcium, 1.95% sulfur, 320 TBN); OLOA™ 218A (5.25% calcium, 2.4% sulfur, 147 TBN); OLOA™ 219 (9.25% calcium, 3.3% sulfur, 250 TBN); and OLOA™ 247E (12.5% calcium, 2.4% sulfur, 320 TBN). All of these calcium phenates are available from the Chevron Chemical Company, Oronite Additives Division, Richmond, Calif. Other representative commercially available calcium phenates include LUBRIZOL™ 6499 (9.2% calcium, 3.25% sulfur, 250 TBN); LUBRIZOL™ 6500 (7.2% calcium, 2.6% sulfur, 200 TBN); and LUBRIZOL™ 6501 (6.8% calcium, 2.3% sulfur, 190 TBN). All of these phenates are available from the Lubrizol Corporation of Wickliffe, Ohio. TBN's may be determined using ASTM D 2896.

Detergents that can be used include oil-soluble neutral and overbased sulfonates, phenates, sulfurized phenates, thiophosphonates, salicylates, and naphthenates and other oil-soluble carboxylates of a metal, for example the alkali or alkaline earth metals, e.g., barium, sodium, potassium, lithium, calcium, and magnesium. In an embodiment, an overbased calcium sulfonates having TBN of from about 20 to about 450, overbased calcium phenates and sulfurized phenates having TBN of from about 50 to about 450, and overbased magnesium or calcium salicylates having a TBN of from about 20 to about 450 can be used. Combinations of detergents can be used.

The fluid composition includes, but is not limited to, fluid compositions such as those suitable for use as an automatic transmission fluid (ATF), continuously variable transmission fluid, manual transmission fluid, and a fluid used in dual clutch transmissions. The at least one lead corrosion inhibitor can also be used in other fluid compositions, such as gear lubricants and fuels.

It is believed, without being limited to any particular theory, that a composition comprising the at least one lead corrosion inhibitor can meet the standards for an oxidation test which measures the change in the total acid number. An example of an oxidation test is the MERCON® Aluminum Beaker Oxidation Test (ABOT), FMC BJ 10-4, revision 1, 2003. Using this test a composition comprising the at least one lead corrosion inhibitor can have a change in the total acid number of less than or equal to 4 at 250 hours. The MERCON V® Aluminum Beaker Oxidation Test (ABOT) requires a composition to have a change in total acid number of less than 3.5 at 300 hours. As a further example, the G.M. DEXRON®-III, H Revision, ATF GMN10055, oxidation test, October 2003, requires a composition to have a change in total acid number less than 3.25, and the cycling test requires a composition to have a change in total acid number of less than 2.0.

A composition comprising the at least one lead corrosion inhibitor can also pass a lead coupon test. For example, at the conclusion of the oxidation tests, the lead coupon can be evaluated based upon its appearance and based on its weight. The weight of the lead coupon can be evaluated by weighing the lead coupon before and after the test. For an accurate measurement at the conclusion of the test, the lead coupon should be wiped to remove any corrosive deposits before it is weighed. A lead coupon exposed to a composition of the present disclosure can possess a change in weight that is less than or equal to 3%, and for example less than or equal to 2% before and after wiping. In one embodiment, the concentration of the lead in the fluid can be measured.

The at least one lead corrosion inhibitor can also be added to at least one additive in the appropriate proportions thereby providing a multifunctional fuel additive package. Examples of at least one additive which may be used include, but are not limited to, dispersants, detergents, antioxidants, carrier fluids, metal deactivators, dyes, markers, corrosion inhibitors, biocides, antistatic additives, drag-reducing agents, demulsifiers, dehazers, anti-icing additives, anti-knock additives, anti-valve-seat recession additives, lubricity additives, combustion improvers, cold flow improvers, friction modifiers, antiwear agents, antifoam agents, viscosity index improvers, antirust additives, seal swell agents, metal deactivators, and air expulsion additives.

In selecting at least one additive, it is important to ensure that the selected additive is/are soluble or stably dispersible in the finished composition, are compatible with the other components of the composition, and do not interfere significantly with the performance properties of the composition, such as friction, rust inhibition, corrosion inhibition, improved wear, and improved lead compatibility, needed or desired, as applicable, in the overall finished composition.

For the sake of convenience, the at least one additive may be provided as a concentrate for dilution. Such a concentrate forms part of the present disclosure and typically comprises from about 99 to about 1% by weight additive and from about 1 to about 99% by weight of solvent or diluent for the additive, which solvent or diluent may be miscible and/or capable of dissolving in the fuel in which the concentrate may be used. The solvent or diluent may, of course, be the low sulfur fuel itself. However, examples of other solvents or diluents include white spirit, kerosene, alcohols (e.g. 2-ethyl hexanol, isopropanol and isodecanol), high boiling point aromatic solvents (e.g. toluene and xylene) and cetane improvers (e.g. 2-ethyl hexylnitrate). Of course, these may be used alone or as mixtures.

In general, the at least one additive may be employed in minor amounts sufficient to improve the performance characteristics and properties of the base fluid. The amounts will thus vary in accordance with such factors as the viscosity characteristics of the base fluid employed, the viscosity characteristics desired in the finished fluid, the service conditions for which the finished fluid is intended, and the performance characteristics desired in the finished fluid.

It will be appreciated that the individual components employed can be separately blended into the base fluid or can be blended therein in various subcombinations, if desired. Ordinarily, the particular sequence of such blending steps may not be crucial. Moreover, such components can be blended in the form of separate solutions in a diluent. According to various embodiments, however, the additive components may be blended in the form of a concentrate, as this simplifies the blending operations, reduces the likelihood of blending errors, and takes advantage of the compatibility and solubility characteristics afforded by the overall concentrate.

According to various embodiments, the transmission fluid composition can be used in the transmission of a vehicle, such as in a torque converter.

Moreover, the at least one at least one lead corrosion inhibitor can be used in a lubricant composition. The lubricant composition can be used to lubricate any machinery, including any machinery having lead parts, such as an at least one bushing in the transmission of a vehicle engine and any gears in a vehicle.

EXAMPLES

Example 1

Corrosion Test for Lubricants

The component to be tested was weighed to the nearest milligram and charged into a 25 by 150-mm test tube. Typically the components were tested such that their concentration in finished lubricant was 0.04 to 0.5% by weight. 20.0 g of a typical automatic transmission fluid was charged into the test tube. A lead coupon 0.81 cm thick by 2.5 cm square was bent into a semi-circle and inserted into the tube. The tube was placed in an oil bath at 150° C. The tube was gently shaken by hand twice every 24 hours, for about 90 hrs. Upon completion of the test the lead coupon was removed from the fluid and washed with heptane and air dried. The appearance of the coupon and the end of test fluid was recorded. The coupon was washed with THF and wiped clean. The post cleaning weight of the coupon was recorded and the end of test fluid was analyzed for the presence of lead by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP). Both of these tests measure the degree of the lead corrosion.

The concentration of lead in the fluid was tested in several compositions comprising at least one of the at least one lead corrosion inhibitor and a high TBN detergent. The statistics were calculated and are shown below. The negative coefficient estimates signify that the additives reduced lead corrosion as measured by the amount of lead in the fluid at the end of the test.

TABLE 1
Lead corrosion
inhibitor (0-0.15%)	High TBN Detergent (0-0.15%)	Lead con. (ppm)
1.00	1.00	1869
−1.00	1.00	2221
1.00	−1.00	1879
1.00	1.00	1294
1.00	1.00	1476
−1.00	−1.00	3173
−1.00	1.00	1983
1.00	1.00	1065
−1.00	−1.00	3115
−1.00	−1.00	3335
1.00	−1.00	2278
0.00	0.00	2214
1.00	−1.00	1861
−1.00	1.00	2011
0.00	0.00	1934
1.00	−1.00	2540
−1.00	1.00	1959
−1.00	−1.00	2941
	Factor	Coefficient estimate
	Intercept	+2117.20833
	Lead corrosion	−475.04167
	inhibitor
	High TBN	−456.29167
	Detergent
	Lead corrosion	+92.45833
	inhibitor * Detergent

In this system, the corrosion of the lead coupons was severe. Lead weight loss was as high as 0.65% and the concentration of the lead in the fluid was as high as 3300 ppm. The most significant model (95% R²) showed linear effects from the at least one lead corrosion inhibitor (99.9%) and the high TBN detergent (99.9%). The model showed the negative interaction between the at least one lead corrosion inhibitor and the detergent was significant at the 94% confidence level. The coefficient for the at least one lead corrosion inhibitor and the high TBN detergent were nearly identical showing that both additives were equivalent in reducing lead loss at this level. The coefficient for the negative interaction term was approximately 20% the size of the main effects.

The percent weight loss of the lead coupon was measured in compositions comprising at least one of the at least one lead corrosion inhibitor and a low TBN detergent.

TABLE 2
Lead
corrosion
inhibitor	Low TBN	Lead Loss	Lead Conc.
(0.09-0%)	Detergent (0-0.05%)	(%)	(ppm)
+1	−1	0.085	162
−1	−1	0.32	1599
−1	+1	0.16	656
+1	+1	0.082	157
−1	+1	0.096	290
		COEFFICIENT
	FACTOR	ESTIMATE
	Intercept	19.96
	EP	−11.29
	Detergent	−4.29
−1	+1	0.24	1208
−1	−1	0.28	1392
+1	+1	0.023	49

The data in Table 2 shows that the corrosion inhibitor (99.9% confidence level) was extremely effective in reducing lead corrosion based on weight loss while low TBN detergent (96%) was not quite as effective. The model gave a R² of 92%.

Further, the percent weight loss of the lead coupon was measured in compositions comprising at least one of the at least one lead corrosion inhibitor, a low TBN detergent, and a high TBN detergent.

TABLE 3
	Lead
	corrosion
Base	inhibitor	Low TBN	High TBN	Lead wt. loss	Lead conc.
Oil	(0.04-0.3%)	(0-0.08%)	(0-0.08%)	(mg)	(ppm)
A1	1.00	1.00	1.00	17.4	116
A2	−1.00	−1.00	−1.00	24	470
A2	−1.00	−1.00	−1.00	30	821
A1	1.00	1.00	1.00	4	19
A2	1.00	−1.00	−1.00	8.4	37
A1	−1.00	−1.00	−1.00	48	1835
A2	1.00	1.00	1.00	6.6	38
A1	1.00	−1.00	−1.00	9.2	221
A2	1.00	−1.00	−1.00	1.8	41
A1	−1.00	1.00	1.00	20.7	895
A1	−1.00	1.00	1.00	12.9	415
A1	1.00	−1.00	−1.00	3.1	33
A2	−1.00	1.00	1.00	16.9	265
A2	−1.00	1.00	1.00	7.2	115
A1	−1.00	−1.00	−1.00	32.4	1155
A2	1.00	1.00	1.00	4.6	15
A2	1.00	0.25	0.25	7.8	34
A2	1.00	0.25	0.25	6.7	33
A1	0.23	0.00	0.00	14	150
A1	0.23	0.00	0.00	10.2	60
A1	0.23	0.00	0.00	10.7	129
	Factor	Coefficient estimate
	Intercept A1	17.1
	Intercept A2	13.1
	Lead corrosion	−8.34102
	inhibitor
	High TBN detergent	−4.06863
	Low TBN detergent	−3.85613
	Lead corrosion	+5.51887
	inhibitor * High TBN
	Detergent

The results showed that once again the at least one lead corrosion inhibitor was statistically significant (99.9% confidence level) and exhibited the largest effect on reducing lead corrosion. Low TBN detergent and high TBN detergent also exhibited beneficial statistically significant linear effects (99.9% confidence level). The size of the effects for the detergents were virtually equivalent and approximately half of that for the at least one lead corrosion inhibitor. There was a statistically significant negative interaction between the high TBN detergent and the at least one lead corrosion inhibitor (99.9%). The magnitude of the effect was on the order of the detergents themselves. Because the at least one lead corrosion inhibitor is acidic, the interaction could be explained on the basis of simple acid base reaction between the at least one lead corrosion inhibitor and the detergent in the bulk fluid. Because the low TBN detergent is less basic than the high TBN detergent the interaction is not observed. However, a closer examination of the data showed that when the at least one lead corrosion inhibitor concentration was low (and the lead corrosion was high), the high TBN detergent was actually beneficial. In some applications, this interaction can have little practical consequences. In a system that is non-corrosive with high levels of at least one lead corrosion inhibitor, the detrimental effect of the interaction may not be measurable. In a system that is highly corrosive with low levels of at least one lead corrosion inhibitor the benefit of high TBN detergent will make little difference.

Example 2

MERCON Aluminum Beaker Oxidation Test (ABOT), FMC BJ 10-4, Revision 1,—2003

The test used an aluminum beaker and head that was fitted with a stainless steel drive shaft. The shaft powered a gear pump that circulated the test fluid and pumped air at 5.0 ml/minute. Lead strips were suspended in the fluid to be tested. The lead strip was weighed prior to the start of the test. The fluid was heated to 150° C. for about 100 hours. After 100 hours the lead strip was removed, washed, and wiped of fluid and debris. The post-wipe weight was recorded and the results were reported in terms of percent weight loss relative to the new strip. After the lead strip was removed the test was continued. The end of test measurements on the fluid consisted of the IR, TAN, and kinematic viscosity. Pass/fail limits were based on the change between the new and used measurements. The limit for the 100 hour lead loss is 3% maximum.

Three runs were conducted on compositions comprising at least one of a lead corrosion inhibitor and a high TBN detergent.

TABLE 4
Lead corrosion	High TBN	Weight	Weight	Weight
inhibitor (0-0.5%)	Detergent (0-0.15%)	loss (%)	loss (%)	loss (%)
0.5	0			.01
0.15	0.15	3.5	2.4
0.15	0	0.6	0.1
0	0.15	3.3	6.3
0	0	4.6	2.8	3.3
0.075	0.075		0.8

The data shows that within each set of tests, lead corrosion was improved by the addition of the at least one lead corrosion inhibitor and the combination of the at least one lead corrosion inhibitor and the high TBN detergent. The combination of the two additives reduced lead corrosion relative to the baseline by 24% and 15%, respectively. There were 85% and 95% reductions in the lead corrosion due to the at least one lead corrosion inhibitor when it was present at 0.15%. When the at least one lead one lead corrosion inhibitor was present at 0.5% there was very minimal lead corrosion. The first data set shows that the high TBN detergent reduced lead corrosion by 29% relative to the baseline. However, the second data set shows a 127% increase in lead corrosion. Under the conditions of the ABOT, the high TBN detergent can interact with the carboxylic acids that are formed and result in an increase in lead corrosion relative to the baseline.

For the purposes of this specification and appended claims, unless otherwise indicated, all numbers expressing quantities, percentages or proportions, and other numerical values used in the specification and claims, are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

It is noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the,” include plural referents unless expressly and unequivocally limited to one referent. Thus, for example, reference to “an antioxidant” includes two or more different antioxidants. As used herein, the term “include” and its grammatical variants are intended to be non-limiting, such that recitation of items in a list is not to the exclusion of other like items that can be substituted or added to the listed items.

While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or can be presently unforeseen can arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they can be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.

Claims

1. A transmission fluid composition comprising a lead corrosion reducing effective amount of at least one lead corrosion inhibitor selected from the group consisting of sulfurized alkylphenols; phosphosulfurized hydrocarbons; substituted or unsubstituted thiocarbamates; substituted or unsubstituted thiazoles; substituted or unsubstituted triazoles; substituted or unsubstituted thiadiazoles.

2. The transmission fluid composition according to claim 1, wherein the at least one lead corrosion inhibitor is present in the composition in an amount ranging from about 0.01% to about 5% by weight relative to the total weight of the composition.

3. The transmission fluid composition according to claim 1, wherein the at least one lead corrosion inhibitor is present in the composition in an amount ranging from about 0.05% to about 3% by weight relative to the total weight of the composition.

4. The transmission fluid composition according to claim 1, wherein the at least one lead corrosion inhibitor is present in the composition in an amount ranging from about 0.2% to about 1% by weight relative to the total weight of the composition.

5. The transmission fluid composition according to claim 1, wherein the composition is selected from the group consisting of automatic transmission fluids, continuously variable transmission fluids, manual transmission fluids, and fluids used in dual clutch transmissions.

6. The transmission fluid composition according to claim 1, wherein the at least one lead corrosion inhibitor is selected from the group consisting of dimercapto-1,3,4-thiadiazoles, 2-mercaptobenzothiazoles, and dithiocarbamates.

7. The transmission fluid composition according to claim 1, further comprising at least one overbased alkaline-earth metal phenate.

8. The transmission fluid composition according to claim 7, wherein the at least one overbased alkaline-earth metal phenate is present in the composition in an amount ranging from about 0.01% to about 5% by weight relative to the total weight of the composition.

9. The transmission fluid composition according to claim 7, wherein the at least one overbased alkaline-earth metal phenate is present in the composition in an amount ranging from about 0.04% to about 3% by weight relative to the total weight of the composition.

10. The transmission fluid composition according to claim 7, wherein the composition passes an aluminum beaker oxidation test with a percent weight loss of a lead coupon of less than or equal to 3%.

11. The transmission fluid composition according to claim 7, wherein the at least one overbased alkaline-earth metal phenate is a calcium phenate.

12. The transmission fluid composition according to claim 7, wherein the at least one overbased alkaline-earth metal phenate has a TBN ranging from about 150 to about 450.

13. The transmission fluid composition according to claim 7, wherein the at least one overbased alkaline-earth metal phenate has a TBN ranging from about 25 to about 150.

14. The transmission fluid composition according to claim 1, further comprising at least one additive selected from the group consisting of dispersants, detergents, antioxidants, carrier fluids, metal deactivators, dyes, markers, corrosion inhibitors, biocides, antistatic additives, drag-reducing agents, demulsifiers, dehazers, anti-icing additives, anti-knock additives, anti-valve-seat recession additives, lubricity additives, combustion improvers, cold flow improvers, friction modifiers, antiwear agents, antifoam agents, viscosity index improvers, antirust additives, seal swell agents, metal deactivators, and air expulsion additives.

15. A vehicle comprising a transmission, the transmission including the transmission fluid composition according to claim 1.

16. The vehicle according to claim 15, further comprising at least one lead part.

17. A method for inhibiting lead corrosion of machinery comprising providing to machinery a fluid composition comprising at least one lead corrosion inhibitor selected from the group consisting of sulfurized alkylphenols; phosphosulfurized hydrocarbons; substituted or unsubstituted thiocarbamates; substituted or unsubstituted thiazoles; substituted or unsubstituted triazoles; substituted or unsubstituted thiadiazoles.

18. The method according to claim 17, wherein the fluid composition is provided to an engine.

19. The method according to claim 17, wherein the fluid composition is provided in a transmission.

20. A composition comprising at least one lead corrosion inhibitor, wherein the composition meets the standards for an aluminum beaker oxidation test measuring a percent weight loss of a lead coupon.

21. The composition according to claim 20, wherein the percent weight loss of a lead coupon is less than or equal to 3%.

22. The composition according to claim 20, wherein the percent weight loss of a lead coupon is less than or equal to 2%.

23. A vehicle comprising the composition according to claim 20.

24. An automatic transmission comprising the composition according to claim 20.