This friction disc spacer sits between the clutch packs inside the gearbox, maintaining the correct stack height and clamping force for each gear set. It is positioned on the shaft between the driven discs, where its thickness determines the engagement clearance for the pack. A spacer that is too thin or worn causes clutch slip under load; one that is too thick prevents full engagement and leads to gear clash. The spacer is manufactured to the same thickness and diameter as the original component, so the stack height and preload match the factory specification. On reassembly, verify that the spacer is seated squarely against the hub shoulder before torquing the retaining nut.