Mercury Quicksilver High Performance Gear Lube 858058KC1

Mercury Quicksilver High Performance Gear Lube 858058KC1 is a marine gearcase lubricant formulated for outboard and sterndrive lower units. This high-performance SAE 90 gear lube is designed to help protect gears and bearings against wear, corrosion, and the effects of water intrusion in marine gear housings. It is commonly specified for higher-horsepower outboards and Mercury MerCruiser sterndrives where a high-performance gear lubricant is required.

Key Features

• Genuine Mercury Quicksilver marine gear lubricant
• High Performance SAE 90 formula for marine gearcases
• Designed for outboard and sterndrive lower units
• Helps protect against gear wear and corrosion
• Formulated to help protect components in the presence of water contamination
• Commonly used where high-load marine gear protection is required

Engine Compatibility
This lubricant is generally used in outboard lower units and sterndrives that call for Mercury/Quicksilver High Performance Gear Lube SAE 90. It is commonly associated with higher-horsepower outboards and Mercury MerCruiser sterndrive applications. Always confirm the required lubricant against the engine or drive owners manual before ordering.

Serial Number Fitment Notice
Lubricant fitment should always be confirmed by engine model, drive model, and serial number. Mercury and MerCruiser applications can vary by gearcase design and service requirements, so the correct fluid specification should be verified before use.

When This Part Needs Replacement
Replace gear lube during scheduled maintenance, seasonal service, or whenever the gearcase has been opened or drained. It should also be changed if the lubricant shows signs of water contamination, metal debris, discoloration, or breakdown.

Installation Notes
Drain the old gear lube fully and refill the gearcase using the manufacturers recommended procedure. Always verify the correct lubricant specification for the exact application before servicing. New drain and vent screw seals should be used where required during gear lube service.

Alternate / Superseded Part Numbers

• 858058
• 858058K
• 858058KC1

Parts Desk Insight
For Mercury and MerCruiser drives, using the correct gear lube type matters just as much as changing it on time. High Performance Gear Lube is typically chosen for applications that see heavier loads, higher operating demands, or sterndrive use, where extra protection against wear and water intrusion is especially important.

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