Mobile power transmissions, including differentials, final drives and planetaries are susceptible to dirt and water contamination due to their location on equipment, especially in the off-highway and mining conditions. Plus, the hydraulic qualities of automatic transmissions make them even more sensitive to dirt and water.
Dirt particles slide between the sets of gears and wear the metal. The end result is larger particles in the lubrication, which accelerates wear further. Water contamination entrained in oil can cause erosion, corrosion, cavitation and hydrogen embrittlement. Left unchecked, water can saturate the lubrication and become free water, accelerating the damage.
Testing can identify low levels of water and dirt, providing time to change the fluid and fix the contamination source before wear occurs.