Gearboxes operating under moderate pressures may call for an AGMA 6, ISO VG 320 moderate-pressure Gear Lubricant. These lubricants are formulated with excellent, performance-enhancing additives that extend systems life and greatly contribute to operation safety and efficiency. Due to the environments in which they work, moderate-pressure gearboxes are often dealing with increased exposure to moisture, high temperatures, and high pressures - accordingly, moderate-pressure gear lubes seek to respond well to moisture exposure and perform consistently in the presence of increased temperature and pressure.
ISO VG 320 oils have a midpoint kinematic viscosity of 320 mm2/s (or Cst, centistokes). This number is equivalent to an average of the minimum and maximum viscosities derived from AGMA testing. In the case of an AGMA 6 oil, these numbers are 288 mPa.S and 352 mPa.S respectively. Though these numbers do roughly equate to the same thing, it is best to consult with OEM specifications before employing any new oil in a system or machine.