This connecting sleeve with keys is a bushing that transmits torque from the hydraulic pump shaft to the pump's internal rotating assembly. It sits inside the pump housing, where the keys engage matching slots in the shaft and the pump rotor to prevent slippage under load. A worn sleeve or sheared key causes the pump to lose drive, resulting in a sudden loss of hydraulic flow to the tractor's steering, lift, or implement circuits. As an original AGCO part, the sleeve is machined to the same internal and external dimensions as the factory component, so it maintains the correct interference fit in the housing without requiring shimming or modification. On installation, ensure the keys are fully seated in their grooves and that the pump shaft rotates freely before closing the housing.