20w50 engine oil is actually roughly the same viscosity as 80w90 gear oil because they don't use the same scale BUT unless your transmission calls for engine oil you shouldn't use it as the additive package is all wrong. Engine oil has additives that cause a high TBN to neutralize the acidic products of combustion and additives like detergents to help clean away the soot and deposit it in the filter (which is why oil turns black) Gear oil has lots of sulfur in it so that it can handle the extreme pressure and shearing forces present with meshing gears.
www.synlube.com
Is ordinary 20/50 engine oil ok for a gear box?
Linear Mode
