This sealing ring fits into the gearbox housing, where it prevents oil leakage between the rotating shaft and the stationary housing. It sits in the seal bore and contacts the shaft surface to retain lubricant inside the gearbox and exclude dirt and moisture. A worn or hardened ring allows oil seepage past the shaft, which can lead to low lubricant levels and gear damage. The ring is manufactured to match the original seal groove geometry, so it seats correctly in the housing without modification. On installation, ensure the sealing lip faces the lubricant side and that the bore is clean and free of burrs.