This gearbox disc is a rotating component inside the transmission housing that transfers torque between gear sets. It sits on the shaft between the input and output stages of the transmission, engaging with the clutch pack to select the desired gear ratio. A worn disc causes slippage under load, leading to delayed engagement or incomplete power transfer. The disc is manufactured to the original thickness and surface finish, which the clutch pack relies on for consistent clamping force and shift timing. On reinstall, verify the disc stack height and torque the clutch retaining bolts to specification.