Mercury Quicksilver High Performance SAE 90 Gear Lube 5 Gallon 858008K01
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Mercury Quicksilver High Performance SAE 90 Gear Lube — 5 Gallon — 858008K01
| Part Number | 858008K01 | Mercury Catalog: 92-858008K01 |
| Current Mercury Replacement | 8M0222055 |
| Brand | Mercury Marine / Quicksilver |
| Official Product Type | High Performance SAE 90 Marine Gear Lubricant |
| System | Gearcase / Lower Unit / Sterndrive |
| Size | 5 US gal / 18.9 L pail |
| Viscosity | SAE 90 |
| Recommended For | Engines 75 HP and above |
| GTIN / UPC | 745061651050 |
| HS Code | 271019 |
Compatible Applications
Mercury specifies High Performance SAE 90 Gear Lube for the following applications. Always confirm the correct lubricant specification in the service manual for your specific engine model and serial number before servicing.
- Mercury outboard lower units — 75 HP and above
- Mariner outboard lower units — 75 HP and above
- MerCruiser Alpha One sterndrives
- MerCruiser Bravo One, Bravo Two, Bravo Three sterndrives
- Mercury jet pumps
- Mercury Sport Jet applications
- Any Mercury or MerCruiser gearcase specifically calling for High Performance SAE 90 Gear Lube
Important: This product is formulated for high-load gearcases and should not be substituted for standard gear lubricant, engine oil, or transmission fluid, even when the viscosity appears similar. Confirm the specification in your service manual.
Cross-Reference / Superseded Part Numbers
- 858008K01 (primary)
- 92-858008K01 (Mercury catalog format)
- 8M0222055 (current Mercury replacement for 858008K01)
- 858008Q01 / 92-858008Q01 (Quicksilver-branded equivalent)
- 8M0222056 (current Quicksilver replacement for 858008Q01)
858008K01 and 858008Q01 are interchangeable Mercury- and Quicksilver-branded references for the same 5-gallon High Performance Gear Lube formulation.
Service Interval
Change gear lube at the interval specified in the Mercury service manual for the exact engine model. As a general guide:
- Outboard lower units: every 100 hours or annually, whichever comes first
- MerCruiser sterndrives: every 100 hours or annually, whichever comes first
- Any time milky, contaminated, or metallic-debris-laden lube is found during inspection
- Any time the gearcase is opened for internal service or seal replacement
When to Change Gear Lube
Do not wait for symptoms before inspecting the gearcase lubricant. Change it proactively and inspect closely for:
- Milky or emulsified lubricant — indicates water intrusion; diagnose the source before refilling
- Metallic particles or fine debris in the drained lube
- Burnt or unusually dark lubricant
- Any time the gearcase is disassembled or seals are replaced
Service Notes
- Drain the old lubricant completely with the unit trimmed down to ensure full drain
- Inspect drain and vent screw seals and replace if compressed, damaged, or leaking
- Fill from the bottom drain port up through the vent hole until lube appears at the vent — follow the Mercury service procedure for the exact gearcase
- Use an appropriate gear lube pump; the Mercury MerCruiser Gear Lube Pump Kit 8M0072135 is compatible with bulk pails
- Recheck vent and drain screws for leaks after the first short run
The 5-gallon / 18.9 L pail is the preferred size for marine service shops, marinas, and operators servicing multiple lower units or sterndrives per season.
Related Parts
- Quicksilver High Performance SAE 90 Gear Lube & Pump Kit – 8M0222069
- MerCruiser High Performance Gear Lube 8M0222063
- Mercury MerCruiser Gear Lube Pump Kit 8M0072135
- Mercury Quicksilver Lower Unit Seal Kit 26-33144A2 — MerCruiser Alpha One Gen 1
- Mercury MerCruiser Quicksilver 8M0187157 Gearcase Drain & Fill Screw Seal
- Mercury MerCruiser Blue Seal 8M0187157
- Sierra Hi-Performance Synthetic Blend Marine Gear Lube 18-9650-2 — 80W-90 GL-5 — 1 Quart
Parts Desk Insights
The 5-gallon pail is the right call for any shop or marina doing regular seasonal lower-unit and sterndrive services — the cost-per-litre is significantly better than individual bottles, and having a pump kit on hand makes the fill process faster and cleaner. The most common issue we see is confusion between High Performance and standard gear lube — Mercury rates the high-performance formula for 75 HP and above, and it is the correct spec for Bravo drives and higher-output outboards. If you find milky gear lube at service time, do not just refill and call it done — milky lube almost always means a seal is letting water in, and that problem needs to be found before the new lube goes in.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.