This expansion ring sits inside the gearbox housing and applies radial force against the basket assembly to maintain tension between the clutch pack and the rotating drum. It occupies the annular space between the basket wall and the hub, where its spring action compensates for thermal expansion and wear. When the ring loses its preload, the clutch pack can slip under load, causing engagement delay and heat buildup. The original AGCO part is formed to the same free diameter and cross-section as the factory ring, so it restores the correct clamping force without requiring shim adjustments. On reinstallation, verify that the ring seats fully into its groove and that the gearbox housing seal is replaced.