The info I was able to find in older threads did not fully answer this question, maybe somebody can educate me. The commonly used EP additives in GL-5 lubricants are suppost to react with the surface of ferrous components to form some sort of iron sulfate and phosphate, if I understand this correctly. Then there are some metal deactivators to avoid the EP additives to react with yellow metals, because S&P are "too corrosive" for yellow metals.
1) Does that say that non ferrous components, such as sleeves and bushings made of brass and bronze do not receive any EP protection by S-P type additives at all?
2) Some manufacturers make borate based EP gear oils. Are there other EP technologies to mention? How do other EP additives work on these materials?
3) Do all EP gear lubricants have additional AW additives to protect the non-ferrous parts in question?
4) If one has an axle with no aggressive hypoid set up, or a planetary final drive, it may not need a GL-5 EP level. A number of OEMs of off-road equipment specify some different, non-gear-oil-type of fluid for axles and final drives. Sometimes this is done because the oil has to work as a functional fluid in clutches and "wet brakes", sometimes to reduce lubricant inventory, and sometimes for no obvious reason. My impression is that these fluids are sometimes specified to avoid EP gear oils. What is it that limits the use of todays GL-5 lubricants in axles and final drives? Corrosion potential at high temperatures and/or over long drain intervals? EP-additive brakedown, which is usually worse than that of AW additives? Seal compatibility?
5) Steerable drive axles, like MFD axles on agricultural tractors, mostly use planetary final drives/wheel hub reductions. In many cases, the sun shaft bearing in these units is a single sleeve made of brass or bronze, the clearance is rather high. Wear on these sleeves, as well as on the shaft seal, happens to be an issue. If the seal wears out the drive shaft, this "issue" turns into a costly problem. What is the "best" lubricant for these final drives with their troublesome seals and sleeves?
-a) A high quality SAE 2360 gear oil meeting a number of extended warranty/extended drain requirements?
-b) A THF-type GL-4 lubricant of a higher viscosity (Case IH has an 80w-140)
-c) Caterpillar FDAO, ideally: CAT FDAO Synthetic What kind of chemistry is this?
-d) Some kind of an industrial gear lubricant?
What do people on bitog think and suggest?
1) Does that say that non ferrous components, such as sleeves and bushings made of brass and bronze do not receive any EP protection by S-P type additives at all?
2) Some manufacturers make borate based EP gear oils. Are there other EP technologies to mention? How do other EP additives work on these materials?
3) Do all EP gear lubricants have additional AW additives to protect the non-ferrous parts in question?
4) If one has an axle with no aggressive hypoid set up, or a planetary final drive, it may not need a GL-5 EP level. A number of OEMs of off-road equipment specify some different, non-gear-oil-type of fluid for axles and final drives. Sometimes this is done because the oil has to work as a functional fluid in clutches and "wet brakes", sometimes to reduce lubricant inventory, and sometimes for no obvious reason. My impression is that these fluids are sometimes specified to avoid EP gear oils. What is it that limits the use of todays GL-5 lubricants in axles and final drives? Corrosion potential at high temperatures and/or over long drain intervals? EP-additive brakedown, which is usually worse than that of AW additives? Seal compatibility?
5) Steerable drive axles, like MFD axles on agricultural tractors, mostly use planetary final drives/wheel hub reductions. In many cases, the sun shaft bearing in these units is a single sleeve made of brass or bronze, the clearance is rather high. Wear on these sleeves, as well as on the shaft seal, happens to be an issue. If the seal wears out the drive shaft, this "issue" turns into a costly problem. What is the "best" lubricant for these final drives with their troublesome seals and sleeves?
-a) A high quality SAE 2360 gear oil meeting a number of extended warranty/extended drain requirements?
-b) A THF-type GL-4 lubricant of a higher viscosity (Case IH has an 80w-140)
-c) Caterpillar FDAO, ideally: CAT FDAO Synthetic What kind of chemistry is this?
-d) Some kind of an industrial gear lubricant?
What do people on bitog think and suggest?
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