3. Seal Swell Compositions. Compositions which are designed to keep seals pliable are also well known in the art. A preferred seal swell composition is isodecyl sulfolane. The seal swell agent is preferably incorporated into the composition at about 0.1-3 weight percent. Substituted 3-alkoxysulfolanes are disclosed in U.S. Pat. No. 4,029,587 which is incorporated herein by reference..

4. Friction Modifiers. Friction modifiers are also well known to those skilled in the art. A useful list of friction modifiers are included in U.S. Pat. No. 4,792,410 which is incorporated herein by reference. U.S. Patent 5,110,488 discloses metal salts of fatty acids and especially zinc salts and is incorporated herein by reference for said disclosures. Said list of friction modifiers includes:

• fatty phosphites
• fatty acid amides
• fatty epoxides
• borated fatty epoxides
• fatty amines
• glycerol esters
• borated glycerol esters alkoxylated fatty amines
• borated alkoxylated fatty amines
• metal salts of fatty acids
• sulfurized olefins
• fatty imidazolines
• and mixtures thereof.

The preferred friction modifier is a borated fatty epoxide as previously mentioned as being included for its boron content. Friction modifiers are preferably included in the compositions in the amounts of 0. 1-10 weight percent and may be a single friction modifier or mixtures of two or more.

Friction modifiers also include metal salts of fatty acids. Preferred cations are zinc, magnesium, calcium, and sodium and any other alkali, or alkaline earth metals may be used. The salts may be overbased by including an excess of cations per equivalent of amine. The excess cations are then treated with carbon dioxide to form the carbonate. The metal salts are prepared by reacting a suitable salt with the acid to form the salt, and where appropriate adding carbon dioxide to the reaction mixture to form the carbonate of any cation beyond that needed to form the salt. A preferred friction modifier is zinc oleate.

5. Antiwear/Extreme Pressure Agents.

1. dialkyldithiophosphate succinates of the structural formula
   
   
   
   wherein R, R' and R1 and R1' are independently selected from alkyl groups having 3 to 8 carbon atoms (commercially available as VANLUBE 7611M, from R.T. Vanderbilt Co., Inc.),



2. dithiophosphoric acid esters of carboxylic acid of the formula
   
   
   
   wherein R2 and R2' are alkyl having 3 to 8 carbon atoms and R3 is alkyl having 2 to 8 carbon atoms (commercially available as Irgalube 63 from Ciba Geigy Corp.), and



3. triphenylphosphorothionates of the formula
   
   
   
   wherein n = 1-2, m = 2-3, R3 is alkyl having 1 to 20 carbon atoms, R4 and R5 are hydrogen or alkyl groups (commercially available as Irgalube^® TPPT from Ciba Geigy Corp.);



4. Methylene bis(dialkyldithiocarbamate) wherein the alkyl group contains 4 to 8 carbon atoms (commercially available as VANLUBE^® 7723 from R.T. Vanderbilt Co., Inc.).



5. Phosphorus acid. The lubricating compositions can also preferably include at least one phosphorus acid, phosphorus acid salt, phosphorus acid ester or derivative thereof including sulfur-containing analogs preferably in the amount of 0.002-1.0 weight percent. The phosphorus acids, salts, esters or derivatives thereof include compounds selected from phosphorus acid esters or salts thereof, phosphites, phosphorus-containing amides, phosphorus-containing carboxylic acids or esters, phosphorus-containing ethers and mixtures thereof. In one embodiment, the phosphorus acid, ester or derivative can be a phosphorus acid, phosphorus acid ester, phosphorus acid salt, or derivative thereof. The phosphorus acids include the phosphoric, phosphonic, phosphinic, and thiophosphoric acids including dithiophosphoric acid as well as the monothiophosphoric, thiophosphinic and thiophosphonic acids.



6. Another class of compounds useful to the invention are dithiophosphoric acid esters of carboxylic acid esters. Preferred are alkyl esters having 2 to 8 carbon atoms, as for example 3-[[bis(1-methylethoxy)phosphinothioyl]thio] propionic acid ethyl ester



7. A preferred group of phosphorus compounds are dialkyphosphoric acid mono alkyl primary amine salt as represented by the formula where R1, R2, R3 are hydrogen or alkyl (hydrocarbyl) groups. Compounds of this type are described in U.S. Patent 5,354,484 which is herein incorporated by reference. Eighty-five percent phosphoric acid is the preferred compound for addition to the fully formulated ATF package and is preferably included at a level of about 0.01-0.3 weight percent based on the weight of the ATF.

The synergistic amine salts of alkyl phosphates are prepared by known methods, e.g. a method disclosed in U.S. 4,130,494. A suitable mono-or diester of phosphoric acid or their mixtures is neutralized with an amine. When mono-ester is used, two moles of the amine will be required, while the diester will require one mole of the amine. In any case, the amount of amine required can be controlled by monitoring the neutral point of the reaction where the total acid number is essentially equal to the total base number. Alternately, a neutralizing agent such as ammonia or ethylenediamine can be added to the reaction. The preferred phosphate esters are aliphatic esters, among others, 2-ethylhexyl, n-octyl, and hexyl mono-or diesters. The amines can be selected from primary or secondary amines. Particularly preferred are tert-alkyl amines having 10 to 24 carbon atoms. These amines are commercially available as for example Primene^® 81R manufactured by Rohm and Haas Co.

Zinc salts are preferably added to lubricating compositions in amounts of 0.1-5 weight percent to provide antiwear protection. The zinc salts are preferably added as zinc salts of phosphorodithioic acids or dithiocarbamic acid. Among the preferred compounds are zinc diisooctyl dithiophosphate and zinc dibenzyl dithiophosphate and amyl dithiocarbamic acid. Also included in lubricating compositions in the same weight percent range as the zinc salts to give antiwear/extreme pressure performance is dibutyl hydrogen phosphite (DBPH) and triphenyl monothiophosphate, and the thiocarbamate ester formed by reacting dibutyl amine-carbon disulfide- and the methyl ester of acrylic acid. The thiocarbamate is described in U.S. Pat. No. 4,758,362 and the phosphorus-containing metal salts are described in U.S. Pat. No. 4,466,894. Both patents are incorporated herein by reference.

Antimony or lead salts may also be used for extreme pressure. The preferred salts are of dithiocarbamic acid such as antimony diamyldithiocarbamate.

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