Mercury - Quicksilver Shift Lever Assembly Gear System Component Steel Construction 45518A3. Overview. Every smooth gear change on a MerCruiser starts with this small but vital part. The Mercury Marine 45518A3 Quicksilver Shift Lever Assembly keeps your sterndrive shifting clean and precise. It's the internal lever that connects your control cable to the clutch system, allowing you to shift into gear without grinding or hesitation. Designed for MerCruiser MC-I, R, MR, Alpha One, and Alpha One Ge