This sealing ring sits in the distribution gearbox of a self-propelled forage harvester. It prevents oil leakage between the gearbox housing and the rotating shaft, maintaining internal pressure and keeping contaminants out of the lubricant circuit. A worn or hardened ring allows oil to seep past the shaft, which can lead to low lubricant levels and accelerated gear wear. The ring is manufactured to the original profile, matching the seal groove geometry in the housing so no additional shimming or adapter is required. On reinstallation, ensure the sealing surface is clean and free of burrs before fitting the ring.