US2850452A - Lubricant - Google Patents

Description

United States Patent LUBRICANT Thoburn P. Sands, Maplewood, James B. Davis, Kirkwood, and Elijah P. Cunningham, Webster Groves, M0., assignors to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing. Application February 15, 1955 Serial No. 488,435

6 Claims. (Cl. 25232.7)

This invention relates to new and improved lubricant compositions which are capable of maintaining an effective lubricant film between engaged surfaces under high load pressures and high rubbing speeds.

It is well knoWn that the ordinary type of hydrocarbon lubricant comprised only of a petroleum fraction is incapable of withstanding the enormous pressures encountered between engaged surfaces in various types of modern machinery, such as the hypoid gears used in motor vehicles. This fact has led to the development of so called extreme pressure lubricants. Such lubricants are composed of a lubricating oil base having incorporated therein a small amount of a chemical ingredient which will form, or which is capable of reaction under extreme pressure conditions to form, a lubricant film capable of withstanding these abnormally high pressures. The added ingredients are known to the art as E. P. (extreme pressure) additives, or E. P. bases. Among the substances which have been used for this purpose are sulfur, both free and chemically combined. Various chlorine and phosphorus compounds have also been used, principally chlorinated hydrocarbons and esters of various phosphorus acids. Combinations of these types of chemical ingredients have also been employed. None of the E. P. base formulations proposed up to the present time, however, have proved satisfactory over the range of service conditions encountered in automotive hypoid gears as exemplified in toto by the Ll9645, L--545 and VVL-'761 tests discussed hereinafter. Thus, whereas one B. P. lubricant will provide satisfactory lubrication under conditions exemplified by one or two of these tests, no one lubricant has been found to give adequate lubrication protection under all of these types of service conditions.

It is the object of this invention to provide an E. P. lubricant which is capable of maintaining a lubricant film, and thus providing highly efiicient lubrication, under the extreme pressure conditions of both high speed and heavy load service. Other objects will appear from the following detailed description of the invention.

The invention resides in the discovery of a unique combination of two base ingredients, which combination provides outstanding eifectiveness as an E. P. additive for hypoid gear lubricants. These two ingredients are the following:

(1) A chlorinated aliphatic material in which the more reactive part of the chlorine has been replaced with a thiocarbonate group.

(2) An oil-soluble polyvalent metal salt of a thiophosphoric acid having two hydrocarbon substituents.

In order that the invention may be readily and fully understood, the several components which make up the novel extreme pressure lubricant will now be described in detail, including examples of procedures which may be followed in preparing these materials and test results demonstrating the outstanding effectiveness of the conteinplated lubricant compositions.

" ice LUBRICANT OIL BASE The oil which forms the major proportion, from about to about 96 percent, by weight, of the gear lubricant composition herein contemplated may be any suitable lubricating oil, such as an oil derived from the refinement of a petroleum crude oil. The viscosity of the oil may vary, depending upon the intended application of the finished lubricant, from about 1 to about 10,000 centistokes at 100 F. Particularly preferred for use in this invention, i. e. in the hypoid gears of automotive vehicles, are lubricating oils having viscosities from about 10 to about 1500 centistokes at 100 F. The oil should, of course, also be selected on the basis of suitable pour point and viscosity index characteristics for the specific purpose intended, it being understood that the desired characteristics of the finished lubricant may be obtained by the addition of lubricating oil additives known to provide the desired effects on these properties in the oil.

CHLORINATED ALIPHATIC COMPOUND-THIC- CARBONATE REACTION PRODUCT As indicated hereinabove, this component of the new composite additive is a polychlorinated aliphatic material, or a polychlorinated material predominantly aliphatic in nature, in which part of the chlorine is replaced by a thiocarbonate group.

The preferred procedure which may be followed in synthesizing this material involves substantial chlorination of an aliphatic compound or a predominantly aliphatic material, such as a petroleum naphtha, followed by reaction of the chlorinated material with an alkali or an alkaline earth metal salt of an alkyl thiocarbonic acid in such proportions and under such conditions that only part, preferably about one-third, of the chlorine (that is, the more reactive chlorine) is replaced by the alkyl thiocarbonate group.

In the chlorination step, the aliphatic material is chlorinated to such an extent that the final chlorinated product corresponds to a polychlor compound, and in the case of petroleum naphtha the chlorination is preferably carried to a point at which the product has an average composition corresponding to a tetra-chlornaphtha. In general, it may be said that chlorination should be carried to the point at which the chlorine content is from about forty percent to about sixty percent, although materialsof lower and higher chlorine content may be used, depending upon the aliphatic constituent.

The range of aliphatic materials which may be chlorinated as the starting material extends from ethane to petroleum wax, the former being a compound containing two carbon atoms and the latter being a predominantly aliphatic material corresponding to a compound having about twenty-four carbon atoms. It has been found, however, that the extremely short-chain compounds, represented by the ethane, and the extremely long-chain compounds, represented by petroleum wax, are somewhat more dilficult to react and are somewhat less elficient in their effect in the final formulation than hydrocarbons of an intermediaate range, and for this reason preference is given to aliphatic materials within the average range of from about 5 to about 15 carbon atoms, particular preference being given to petroleum naphtha (or kerosene), a hydrocarbon material predominantly aliphatic in nature corresponding to a compound having about 10 carbon atoms and having a boiling range of from about C. to about 275 C.

The thiocarbonate group which is used to replace a part of the chlorine is, as has been indicated above, derived from an alkali (Na, K, Li) or alkaline earth (Ca, Sr, Ba) metal salt of a thiocarbonic acid, preferably an alkyl thiocarbonic acid. The thiocarbonate radical may weight, e. g. methyl, ethyl, propyl and butyl.

be a mono-, dior trithiocarbonate, but in general pref- "erence is given to the dithiocarbonate (xanthate) compounds, characterized by the divalent group (OCS The trithi'ocarbonate type of compounds, characterized by thedivalent group (CS have also been prepared.

and have been found to form effective extreme pressure agents in combination with'the chlorinated aliphatic mastituentfrom the standpoint of solubility, etc., and the lower molecular weight alkyl groups give a finished product in which the content of chlorine and characterizing divalent thiocarbonate groups (O CS, OCS or CS is somewhat more highly concentrated.

As examples of the thiocarbonate or xanthate materials which may be reacted with chlorinated aliphatic materials to provide extreme pressure agents of the type contemplated by this invention, sodium or potassium methyl, ethyl, propyl, isopropyl, butyl, amyl, hexyl, octyl, decyl or dodecyl xanthates or the corresponding monoor trithiocarbonates may be used.

It is highly important, as stated above, that the proportions of reactants used and the conditions of reaction be controlled so that the final product contains both chlorine and thiocarbonate characterizing groups in chemical combination with the aliphatic hydrocarbon material. The relative amounts of chlorine and sulphur, or, more specifically, of chlorine and thiocarbonate characterizing groups, in the finished product may be varied over a relatively wide range, but in general it may be said that the finished product should preferably be one which contains from about twenty-five to forty percent chlorine and from about seven to fifteen percent sulphur. Expressing the sulphur content as the equivalent amount of characterizing thiocarbonate groups present in the product, such preferred products are more accurately identified as containing from about ten percent to about twenty-two percent characterizing dithiocarbonate or xanthate (divalent OCS groups or from about seven percent to about seventeen percent characterizing trithiocarbonate (divalent CS groups. For general purposes it may be said that the characterizing-thiocarbonategroup-content is preferably from about seven percent to about twenty-two percent.

The reaction between the chlorinated aliphatic material and the alkali thiocarbonate is preferably carried out in the presence of a relatively low boiling point solvent. For convenience in reaction and purification, the solvent is preferably one in which the chlorinated aliphatic material and the reaction product are highly soluble but in which the alkali thiocarbonate and the alkali chloride are of low solubility. As an example of such a solvent acetone has been found to be highly satisfactory, although other solvents, such as methyl ethyl ketone, may be used. Alcohols may also be used as solvents in this reaction. Solvents such as acetone and methyl ethylketone are particularly desirable since they permit the reaction to proceed but tend to precipitate residual alkali thiocarbonate and chloride, thus permitting the process to be performed and the product substantially purified all in one step.

The general preferred procedure followed in efiecting the replacement of the more highly reactive chlorine in chlorinated aliphatic materials with the thiocarbonate group is to dissolve the chlorinated aliphatic material in the solvent and add the alkali alkyl thiocarbonate in an amountsuflicient to give aproduct. having thedesired terial, but from the standpoint of odor and cost, prefchlorine and sulphur rati Under the conditions of reaction employed materials'have been prepared using from about one-fourth to about twice as much alkali thiocarbonate (xanthate) as chlornaphtha. The preferred ratio, however, is to use a weighted amount of alkali thiocarbonate corresponding to from about forty percent to about seventy percent of the weight of the chlornaphtha used. It will be understood, of course, that these ratios vary with other chlorinated aliphatic materials, depending upon their hydrocarbon and chlorine content, and should also take into consideration the alkyl substituent which is attached to the characterizing thiocarbonate 'group.

As aforesaid, the preferred products contemplated by this invention are those obtained by replacing a part of the chlorine in chlorinated petroleum naphtha with an alkyl xanthate group. These materials are preferred to others in this general class of materials because of their case of synthesis, their cost, etc. An exemplary procedure for preparing such a product, which is termed chlornaphtha-xanthate reaction product or xanthochlornaphtha is the following:

Example A.Chlornaphtha-xanthate reaction product A chlorinated naphtha is first prepared by chlorinating petroleum naphtha (Stoddard solvent) until it contains about fifty-four percent by weight of chlorine. of the chlornaphtha is then dissolved in about 500 parts of acetone and placed in a reaction vessel heated by a water jacket and equipped with stirrer and reflux condenser. xanthate is added and the mixture held at boiling temperature with stirring under reflux for about two hours. The resulting mixture is cooled to room temperature, filtered, and the filtrate subjected to distillation to remove the acetone. After removal of the acetone the product is washed to remove potassium salts and is dried and filtered. The finished reaction product obtained by the foregoing procedure, which for purposes of description herein is termed chlornaphtha-xanthate reaction product or chlornaphtha-isopropyl xanthate reaction product is a dark brown liquid containing about eleven percent sulphur, or more specifically about sixteen percent of the characterizing xanthate (divalent OCS group, and thirty-four percent chlorine.

Variation in xanthate and chlorine content of the reaction product can be obtained by varying the degree of chlorination of the naphtha; by varying the amount of alkali xanthate used, and by varying the hydrocarbon substituent in the alkali xanthate. Thus products of widely varying chlorine and xanthate content are readily possible. In general, as indicated above, a product con taining from about ten percent to about twenty-two percent of the characterizing xanthate group and from about twenty-five percent to about forty percent of chlorine is preferred.

POLYVALENT METAL SALT OF A THIOPHOS- PHORIC ACID These materials are characterized by mineral oil solubility and may be represented structurally as follows no s 7 200 parts To this solution parts of potassium isopropyl lead, mercury, copper, manganese, iron, tin, bismuth, thorium, aluminum, calcium, magnesium and barium.

The oil-soluble metal salts contemplated by this invention may be prepared by a great variety of methods, e. g. by mixing an ester of the structure with an excess of the oxides of the respective polyvalent metals and allowing the mixture to stand at temperature above about 50 C. for a period in excess of about 4 hours. Upon decanting and filtering the desired polyvalent metal salt of a thiophosphoric acid is obtained. The aforedescribed ester is readily obtained by well known methods, for example by reacting about four molecular proportions of an alcohol (ROH) with about one molecular proportion of phosphorus pentasulfide at about 100 C, over a period of about 3-6 hours.

As illustrative of the preparation of a polyvalent metal salt of a thiophosphoric acid contemplated by this invention is the following:

Example B To a suitable reaction vessel is added and intimately mixed approximately 4 molecular proportions of methyl isobutyl carbinol and approximately one molecular proportion of phosphorus pentasulfide. The mix so obtained is heated at 90-100 C. for about three hours employing a pressure slightly below atmospheric. The thiophosphoric acid is decanted from the unreacted phosphorus pentasulfide and admixed with a small amount of water and zinc oxide in excess of that theoretically required. The mixture is heated at about 60 C. for about three hours, cooled and filtered. The dark oily zinc salt so obtained analyzes approximately a weight ratio of one part of phosphorus and approximately 2.2 parts sulfur per one part of zinc. Theoretically the weight ratio is approximately 112.06: 1.05 of phosphorus to sulfur to zinc.

EVALUATION OF ADDITIVE FORMULATION To demonstrate the efiectiveness of the composite additive formulation herein contemplated, laboratory tests were conducted on oil blends of the composite additive formulation and on blends containing only one of the individual components. The laboratory tests were those contained in U. S. Army Specification 2-105B (now Military Specification Mil-L-2105) which describes a multipurpose gear oil suitable as a lubricant for automotive hypoid gears under conditions of service ranging from high speed shock loading to low speed, high torque operation. These tests designated as L-l9-645 and L20545 were developed by the Coordinating Lubricants Research Committee at the request of the Army Ordnance Department for the purpose of testing gear oils suitable as lubricants for automotive hypoid gears. As is well known, many lubricating compositions are satisfactory under one type of operation, such as high speed passenger car service, but are not satisfactory unde others, such as low speed, high torque heavy truck operation. The L-19-645 test measures the high speed performance of a lubricant, while the L-20545 test measures the low speed, high torque perfornance of a lubricant. A detailed description of each of these test procedures may now be found in the CRC Handbook 1946 published by J. J, Little and Ives Company, New York, N. Y. Both of these laboratory tests employ actual gears operating under conditions simulating severe service. Laboratory tests were also conducted on blends of the composite additive formulation and on blends containing only one of the individual components employing the VVL761 test described in Federal Standard Stock Catalog Section IV (Part 5), Federal Specification for Lubricants; Enclosed-Gear, Hypiod Gear, and other types, November 28, 1947. Those familiar with the art will appreciate that this laboratory test as distinguished from an actual road test constitutes one of the most severe tests in the evaluation of gear lubricants.

The following table sets forth the results obtained employing the above-described tests on oil blends of the two component additives of this invention as compared to blends of only one of the components in the oil.

The base oil used in the tests was Mid-Continent SAE grade oil unless otherwise noted. The additive concentrations are expressed in weight percentages based on the oil.

TABLE Base oil plus additive 11-19-645 L-20-545 VV-L-761 10% reaction product of Ex. A-.. Pass Failed Failed. 11% reaction product of Ex. A d0 o- Do. 5% reaction prsrluct o? Ii do..-- Pass D0. 8'27 reaction pror not 0 x.

8 reaction pro not 0 x 253% reaction product: 53f Ex. B i' 8 reaction procuct o x. A

134 87;, reaction product of Ex. B 5% reaction product of Ex. A do do Do 5% reaction product of Ex. B

The component additives of the invention may be blended in the lubricating oil either individually or they may be mixed together to form the composite additive and then blended as such with the oil. The efiective ranges in weight percent based on the oil for the individual additives are the following: (a) from about 2% to about 15% of the chlorinated aliphatic compound-thiocarbonate products and (b) from 1% to about 5% of the oil-soluble polyvalent metal salt of the thiophosphoric acid, the total weight of said additives being not less than 4%. It is particularly preferred that the weight ratio of chlorinated aliphatic compound-thiocarbonate product to polyvalent metal salt of thiophosphoric acid be 15:1 and that the total amount of said additives be in the range of 6% to 12%.

Other oil-soluble polyvalent metal salts of a thiophosphoric acid than zinc di-(methylisobutylcarbinol) dithiophosphate particularly contemplated by this invention comprise Zinc di-(isoamyl) dithiophosphate Zinc di(isohexyl) dithiophosphate Zinc di-(2-ethylhexyl) dithiophosphate Zin di-(iso-octyl) dithiophosphate Zinc di-(cyclohexyl) dithiophosphate Zinc di-(p-methylcyclohexyl) dithiophosphate Zinc di-(benzyl) dithiophosphate This case is a continuation-in-part of our co-pending application Ser. No. 439,914, filed June 28, 1954, now abandoned.

While this invention has been described with respect to certain embodiments it is not so limited and it is to be understood that variations and modifications obvious to those skilled in the art may be made without departing from the spirit or scope of the invention.

ADDENDA VV-L761 shock test as adapted to be run in a laboratory gear setup I. INTRODUCTION In simulated driving a lubricant is tested in a full scale axle. The set is first driven at high speed and road load and then subjected to severe shock by engaging the clutch on a dead engine at 65 M. P. H. in direct drive and finally by engaging the clutch on a dead engine at 45 M. P. H. in second gear.

II. EQUIPMENT A. A 216 cu. in. Chevrolet engine equipped with a truck clutch and 4-speed transmission drives the third member test unit. The third member is installed in a stand ard Chevrolet passenger car rear axle housing which in turn has its axle shafts coupled to two dynamom- 7 eters. 'The :auxiliary equipment necessary to determine and control speeds, loads, temperatures, etc. is also included in the setup.

1. The third members, Chevrolet part No. 3704414,

- 9:37 ratio, are units specially'selected from the production lines.

III. MAINTENANCE AND PREPARATION FOR TEST A. Dynamometers '1. Follow standard maintenance practice for lubrication, etc.

2. Supply suflicient flow of water to dynamometers .to maintain a water discharge temperature below B. Axle housingto install following L-2O tests l. Re-position the stands according to markings on the bedplate.

2. Set housing On stands v.andvtighten the eight bolts that hold it .to the stands.

3. Install appropriate coupling shafts when chan ing from L-20 to Ll9.

4; Connect splines so that the U-joint yokes adjacent to the shafts are in the same plane.

5. Frequently check tightness of all screws used to couple axles to dynamometers.

C. Axle housing-40 prepare for test I 1. Wash housing and axle shafts using Stoddard solvent and a fiber brush. Wipe dry. D. Auxiliary equipment 1. Disengage the low speed tachometer generator gear from the gear on the north end of the north dynamometer.

2. Push the revolution counter switch out of contact with the cam on the north end of the south dynamometer.

E. Engine and transmission 1. Observe good maintenance practice in regard to oil change, spark plugs, valves, etc.

2. When changing from L2O to L-19, change the rear plate or retainer on the transmission. Change from the truck to passenger car U-joint.

F. Third member 1. Select the lowest numbered unit of the shipment in current use.

N te.The units of each shipment received are numbered serially from one by the shipper. When received, they are assigned a shipment number which is painted on each unit.

2. Record unit number and shipment number on the log sheet.

3. Make the best possible drawing of the contact pattern as it shows on the ring gear teeth, both drive and coast sides.

Nata-This was made :by rolling the gears under load as part of the final factory inspection.

4. Remove the pin and differential gear cluster.

5. Clean all accessible parts in the housing by spraying with Stoddard solvent andblowing dry with Nata-Keep the torque tube elevated while spraying and drying the unit so that excess Stod dard solvent will not run into it. Do not attempt to make any adjustments to the assembly.

6. Apply a medium coat of Prussian blue on both drive and coast sides of two ring gear teeth. Turn the coated teeth back and forth through mesh with the pinion.

7. Record the tooth contact indication obtained.

8. Take two backlash determinations at opposite sides of the ring gear.

N0te.--When taking backlash, the gauge should be adjusted so that it is as nearly as possible at right angles to a radius of the ring gear. The pinion must be held from turning by wedging a ham- ..mer handle orother objectbetween the teeth -of the pinion and the side-0f the housing. Backlash rom 0.003 to 0.012 is satisfactory. If outside these limits, do not use for test. '9. Lu-bricate the carrier bearings and pinion bearing with 50 cc. of the test lubricant.

N0te.Tilt the unit at a steep angle with the gears at the upper end to get the lubricant to run into the pinion bearings.

10. Assemble the third member to the housing using a new paper gasket.

11. Assemble the side gears, differential gears, shafts,

locks, spacer, differential pin, and its lock according to standard practice as outlined in the Chevrolet shop manual.

Note-Put a small amount of the test lubricant on the gears and pin.

12. Assemble the cover to the housing using a new cork gasket.

13. Check the location of the thermocouple junction. It should be 1" from the face of the ring gear and 1" above the bottom of the housing.

14. Slide the U-joint ball and its collar over the end of the tube.

15. Raise the front end of the torque tube to about eye level and pour as much test lubricant into the open end of the housing as it will hold (about 150 cc.)

16. Slide the rear U-joint yoke as far into the torque tube as it will go.

17. Lower the torque tube and assemble the U-joint.

N0te.If necessary, adjust the housing stands to give good alignment at the U-joint.

18. Assemble the ball and collar. Use enough shims so that the ball is free enough to be turned by hand but not free enough to have excess clearance.

19. Remove the plug and pour cc. of the test lubricant into the U-joint housing.

20. Put the guards in place between the dynamometers and the axle housing.

21. Weigh 1500:50 g. of the test lubricant into the axle.

IV. OPERATION AND TEST A. Start and warm-up 1. Open the main water valve. 2. Start the engine and let it warm up.

Nata-Ignition voltage is furnished by 6 v. MG set in Cell No. 3.

3. Check spark advance, adjust idle jet, and set idle speed adjustment to give 500 R. P. M. With the hand throttle lever in closed position.

4. Check water flow to exhaust line and heat exchanger.

5. Start motor generator set to supply dynamometer field current.

N0te.The following mended:

(a) Check to see that all voltage and current controls are turned to the decrease end of their travel.

(b) Press motor start button.

(c) Turn the right hand wall switch on (Field Excitation Current).

- (d) Turn on the left hand wall switch (Console Supply). Now the Supply Voltage" indication at the console should be about 50 v.

(e) Adjust the field voltage controls to give 6. Adjust the air pressure of the pneumatic clutch controls to 25 lbs.

B. High speed running 1. Starting with low-low, carefully go up through thegears to directdrive.

sequence is recom- Note (a).*It is suggested that the shift from 1st to 2nd, 2nd to 3rd, and 3rd to 4th, be made at 5, and M. P. H. respectively.

Note (b).-For all the above acceleration, the throttle shouldbe handled so that the vacuum is kept above 15".

2. Slowly accelerate to 60 M. P. H. (keep engine vacuum above 15" to 40 M. P. H. and above 12" to 60 M. P. H.). Press start buttons of dynamometer field switches No. l and No. 2 and apply a load of 35 lbs. on each dynamometer. Adjust throttle to maintain 60 M. P. H. at this load.

3. Record mileage and continue at 60 M. P. H. and 35 lbs. load for 3.8 miles. Record temperature at end.

4. Accelerate at 70 M. P. H. Adjust load to 45 lbs. on each dynamometer.

5. Record mileage and continue 3.8 miles at these conditions. Record temperature at end.

6. Slowly close throttle (to give 1" of vacuum increase every 5 seconds) until a vacuum of 18" is reached, then let the set decelerate to 40 M. P. H. (close throttle). Remove dynamometer load (press dynamometer field switch No. 2 stop) and allow to decelerate to 15 M. P. H. Accelerate to 40 with a 15 vacuum and again close the throttle and allow to decelerate to 15 M. P. H., listening for any howl or noise in the gears that might indicate a failure.

7. If there is any noise that would definitely indicate a failure, disengage the clutch and stop the dynamometers and inspect. If a failure is indicated, stop the test. If no failure is indicated, continue.

8. Accelerate to 75 M. P. H. Apply a load of 50 lbs. on each dynamometer.

9. Record mileage and run at these conditions for 38.0 miles. Record maximum temperature during this part of run.

N0te.Use fan and wet rags on the axle housing as required to keep the temperature below 250 F.

10. Decelerate and make a noise check as in 6 above.

11. Disengage the clutch and stop the gears.

spect as in 7 above.

12. If there is no indication of scoring, take the set up through the gears to direct drive and continue.

C. Direct drive shocks 1. Accelerate to 70 M. P. H. (use a vacuum of about 10" to 60 M. P. H. and a vacuum of about 7 from 60 to 70 M. P. H.). Apply dynamometer load and adjust to 45 lbs. on each dynamometer at 70 .M. P. H.

2. In rapid succession, but not simultaneously, disengage the clutch, close the throttle, and turn off the ignition switch. When the set decelerates to 65, engage the clutch and allow to coast down to 40 M. P. H.

3. Turn on ignition, turn off dynamometer load and accelerate to 70 and repeat 1 and 2 for a total of seven times.

Note (1 ).Since it takes a few seconds for the load to come to equilibrium, it is an advantage to apply the load at about 60 M. P. H. so that the load will be equalized soon after the set reaches 70 M. P. H.

Note (2).--Make sure that the engine stops completely before the clutch is engaged. It may be necessary to change the idling speed, adjusting screw to make sure that the engine stops before the clutch is engaged.

4. Make noise check as in last half of B5 above.

If no objectionable noise or no indication of scoring, continue.

5. Run eight more, making a total of fifteen, direct drive shocks as in 1, 2 and 3 above.

6. Make a noise check and inspection as in 6 and 7 above except that the inspection is made regardless of the results of the noise check.

7. If the gears are not scored, continue.

D. Second gear shocks 1. Take the set up through the gears to third.

Note-Third of the 4-speed truck transmission corresponds to second of the passenger car transmission.

2. Accelerate in third gear to 50 M. P. H. Apply a load of 50 lbs. to each dynamometer. When load and speed are leveled out, in rapid succession disengage the clutch, close the throttle, and turn off the ignition. When the set decelerates to 45 M. P. H., engage the clutch and let decelerate to 20 M. P. H. When 20 M. P. H. is reached, turn the ignition on, turn the dynamometer load off, and accelerate to 50 M. P. H. Apply a load of 50 lbs. and repeat the above for a total of 5 shocks.

3. Following the 5 shocks, shift to direct drive and make a noise check as in the last part of 6 above. If no indication of scoring, continue.

4. Repeat 2 to make a total of 10 third gear shocks. 5. Repeat 3.

6. Stop the set, take a 4-0z. sample, and make a visual inspection.

7. Dissemble the third member. If the gears have scored under the above test conditions, or if the aXle became objectionably noisy at any stage during the tests, the lubricant is considered to have failed.

What is claimed is:

1. An extreme-pressure lubricating composition comprising a major proportion of a mineral lubricating oil and, based upon said oil, (a) from about 2% to about 15% by weight of an oil-soluble product obtained by chemically substituting a part only of the chlorine in a chlorinated aliphatic hydrocarbon material having from 2 to about 24 carbon atoms with an alkyl thiocarbonate group, and (b) from about 1% to about 5% by weight of an oil-soluble polyvalent metal salt of a thiophosphoric acid of the structure,

where M is zinc, where n is 2, and where R contains from 3 to 14 carbon atoms and is selected from the group consisting of alkyl and cycloalkyl radicals, the total weight percent, based on the oil, being not less than 4%.

2. An extreme-pressure lubricating composition comprising a major proportion of a mineral lubricating oil and, based upon said oil, (a) from about 2% to about 15% by weight of an oil-soluble product obtained by chemically substituting a part only of the chlorine in a chlorinated aliphatic hydrocarbon material having from 5 to about 15 carbon atoms with an alkyl thiocarbonate group, and (b) from about 1% to about 5% by weight of an oil-soluble polyvalent metal salt of a thiophosphoric acid of the structure,

sisting of alkyl and cycloalkyl radicals,ithe total Weight percent, based on the oil, being not less than 4%.

3. An extreme pressure lubricating composition comprising a major proportion of a mineral lubricating oil and based upon said oil (a) an oil-soluble product obtained by chemically substituting a part only of the chlorine in a chlorinated petroleum naphtha with an alkyl xanthate group, said product having a chlorine content of from about 25% to about 40% and a characterizing Xanthate, group content of from about 10% to about 22%, and (b) an oil-soluble polyvalent metal salt of a chicphosphoric acid of the structure where M is zinc, where n is 2 and Where R is an alkyl group containing from 5 to carbon atoms, the total weight percent based on the oil of (a) and (b) being in the range of 6% to 12% and the Weight ratio of (a) to (b) being about 15:1.

4. An extreme pressure lubricating composition comprising a major proportion of a mineral lubricating oil and based upon said oil (a) an oil-soluble product obtained by chemically substituting a part only of the chlorine in a chlorinated petroleum naphtha with an isopropyl Xanthate group, said product having a chlorine content of from about 25% to about 40% and a characterizing Xanthate group content of from about 10% to about 22%, 7

12 and '(b) an oil-soluble polyvalent metal salt of a thiophosphoric acid of the structure I n is 2 and where R is CHCHz--CH- CH3 CH3 References Cited in the file of this patent UNITED STATES PATENTS 2,261,047 Assefi Oct. 28, 1941 2,331,005 Story et a1 Oct. 5, 1943 2,364,284 Frueler Dec. 5, 1944 2,516,119 Hersh July 25, 1950 2,631,129 Waugh Mar. 10, 1953

Claims (1)

1. AN EXTREME-PRESSURE LUBRICATING COMPOSITION COMPRISING A MAJOR PROPORTION OF A MINERAL LUBRICATING OIL AND, BASED UPON SAID OIL, (A) FROM ABOUT 2% TO ABOUT 15% BY WEIGHT OF AN OIL-SOLUBLE PRODUCT OBTAINED BY CHEMICALLY SUBSTITUTING A PART ONLY OF THE CHLORINE IN A CHLORINATED ALIPHATIC HYDROCARBON MATERIAL HAVING FROM 2 TO ABOUT 24 CARBON ATOMS WITH AN ALKYL THIOCARBONATE GROUP, AND (B) FROM ABOUT 1% TO ABOUT 5% BY WEIGHT OF AN OIL-SOLUBLE POLYVALENT METAL SALT OF THIOPHOSPHORIC ACID OF THE STRUCTURE,