What type of lubricant is commonly used to protect the gears of the gearbox and of the differential bevel gear set?

Question

DentroTest · Accepted Answer

The gears of the gearbox and of the differential are subjected to enormous mechanical pressures and constant direct metal-to-metal friction. For this reason, they require a lubricant with special characteristics called gear oil (valvulina, or valvolina), which stands out for its high viscosity and its ability to withstand extreme pressures (EP additives). A low-viscosity fluid is no good, because it would drain away quickly and would not maintain the protective film, causing premature wear of the gear teeth. The sump oil is no good either, because it is formulated for engine lubrication, with different thermal properties and tolerances, and cannot withstand the shear stresses of the transmission system.

What type of lubricant is commonly used to protect the gears of the gearbox and of the differential bevel gear set?

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