Hey fellars, just a question on what oil to use in final drives. Machine is working in extreme conditions blade plowing, hard pulling all day, am I better using the standed 50 grade to-4 or would I be better to go for a ep oil. I have herd ep oils are not good for seals, is this true?:confused thanks in advance. Bill.
If you're talking about a Cat machine here I don't receommend the use of any EP oil in Final Drives, it WILL affect the Toric Rings in the Duo-Cone seals and cause expensive (to fix) oil leaks. If you're worried about oil for finals for heavy work on a track-type tractor in a hot climate and want an alternative to SAE 50 TO-4 then go for a SAE 60 oil that meets Cat FD-1 spec.
Thanks nige, just had to ask the question to put my mind at rest.
FD-1 SAE 60 is what goes in new large tractors from new at the factory. For comparison the viscosity between a 50 & a 60 is from ISO 220 to 320.