Lubricating oil compositions for construstion machines

Abstract

Provided is a Zinc-free transmission oil composition for construction machinery comprising: a major amount of an oil of lubricating viscosity, a dithiophosphorylated carboxylic acid compound, a phenate detergent, a friction modifier, and greater than 0.05 wt. % of a sulfur-containing wear inhibitor. Also provided is a method for lubricating the transmission of a construction machine comprising lubricating the transmission with said Zinc-free transmission oil composition.

1 . A Zinc-free transmission oil composition for construction machinery comprising:
 (a) a major amount of an oil of lubricating viscosity,   (b) a dithiophosphorylated carboxylic acid compound,   (c) a phenate detergent,   (d) a friction modifier, wherein the friction modifier is a fatty acid amide, and   (e) greater than 0.05 wt. % of a sulfur-containing wear inhibitor.   
     
     
         2 . The transmission oil composition of  claim 1  wherein the dithiophosphorylated carboxylic acid compound is 3-[[bis(2-methylpropoxy)phosphinothioyl]thio]-2-methyl-propanoic acid. 
     
     
         3 . The transmission oil composition of  claim 1  wherein the dithiophosphorylated carboxylic acid compound is present at 0.025 to 1 wt. %. 
     
     
         4 . The transmission oil composition of  claim 1  further comprising a dispersant. 
     
     
         5 . The transmission oil composition of  claim 1  wherein the sulfurized wear inhibitor is sulfurized olefin. 
     
     
         6 . The transmission oil composition of  claim 1  wherein the sulfurized wear inhibitor is sulfurized isobutylene. 
     
     
         7 . The transmission oil composition of  claim 1  wherein the sulfurized wear inhibitor is present from 0.06 to 2 wt. %. 
     
     
         8 . The transmission oil composition of  claim 1  wherein the phenate detergent is present from 0.05 to 5.0 wt. %. 
     
     
         9 . The transmission oil composition of  claim 1  further comprising a friction modifier. 
     
     
         10 . (canceled) 
     
     
         11 . The transmission oil composition of  claim 1  wherein the friction modifier is present in the composition from 0.01 to 2.0 wt. % on an actives basis. 
     
     
         12 . The transmission oil composition in  claim 1  further comprising at least a second detergent other than the phenate detergent. 
     
     
         13 . A method for lubricating the transmission of a construction machine comprising lubricating the transmission with a Zinc-free transmission oil composition comprising:
 (a) a major amount of an oil of lubricating viscosity,   (b) a dithiophosphorylated carboxylic acid compound,   (c) a phenate detergent,   (d) a friction modifier, wherein the friction modifier is a fatty acid amide, and   (e) greater than 0.05 wt. % of a sulfur-containing wear inhibitor.   
     
     
         14 . The method of  claim 13  wherein the dithiophosphorylated carboxylic acid compound is 3-[[bis(2-methylpropoxy)phosphinothioyl]thio]-2-methyl-propanoic acid. 
     
     
         15 . The method of  claim 13  wherein the dithiophosphorylated carboxylic acid compound is present at 0.025 to 1 wt. %. 
     
     
         16 . The method of  claim 13  further comprising a dispersant. 
     
     
         17 . The method of  claim 13  wherein the sulfurized wear inhibitor is sulfurized olefin. 
     
     
         18 . The method of  claim 13  wherein the sulfurized wear inhibitor is sulfurized isobutylene. 
     
     
         19 . The method of  claim 13  wherein the sulfurized wear inhibitor is present from 0.06 to 2 wt. %. 
     
     
         20 . The method of  claim 13  wherein the phenate detergent is present from 0.05 to 5.0 wt. %. 
     
     
         21 . The method of  claim 13  further comprising a friction modifier. 
     
     
         22 . (canceled) 
     
     
         23 . The transmission oil composition of  claim 13  wherein the friction modifier is present in the composition from 0.01 to 2.0 wt. % on an actives basis. 
     
     
         24 . The method of  claim 13  further comprising at least a second detergent other than the phenate detergent.