This profile ring sits inside the gearbox housing, where it functions as a sealing and locating element between rotating shafts and the housing bore. It prevents lubricant migration along the shaft and maintains the correct axial position of the adjacent bearing or gear. A worn or deformed ring allows oil leakage past the shaft seal, which can lead to low lubricant level and eventual gear or bearing damage. The ring is manufactured to the original cross-section profile and material hardness, so it seats correctly in the housing groove without deformation during installation. On reassembly, ensure the groove is clean and free of burrs before pressing the ring into place.