Synthetic Gear Lubricants are unique in terms of their performance characteristics when employed in gearboxes - these lubricants are often employed in place of Extreme Pressure (EP) gear lubricants when extreme pressure performance capabilities are required. Synthetic lubricants may be able to withstand extreme pressures and extreme temperatures in ways that mineral-based oils cannot; these gear lubricants have the desired increased performance characteristics without the need for EP additives - therefore, most of these lubricants can be used in gearboxes containing yellow metals (check with OEM specifications and Product Data Sheets).
ISO VG 100 oil has a midpoint kinematic viscosity of 100 mm2/s, also referred to as centistokes (cSt). The midpoint is derived by taking the average of both the minimum and maximum kinematic viscosities. In the case of ISO VG 100 oil, those numbers are 90.0 cSt and 110.0 cSt, respectively. AGMA 3S lubricants have a minimum viscosity of 90 mPa.s and a maximum viscosity of 110 mPa.s. These numbers refer to the standard testing mechanisms used to determine how much resistance to flow (i.e. viscosity) these oils demonstrate.