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Sierra 18-6406 Mercruiser U-Joint Assembly GKN Style

Manufacturer

Sierra

<p>For nearly six decades, Sierra has established itself as one of the marine industry's most trusted names in aftermarket engine and drive parts. Founded as a specialized marine parts manufacturer, Sierra has grown into a comprehensive supplier of replacement components, instrumentation, and accessories for both recreational and commercial boating applications. Operating from their 300,000-square-foot distribution center in Litchfield, Illinois, Sierra serves boat owners and marine technicians worldwide with an extensive catalog of parts engineered specifically for the harsh saltwater environment.</p><h3>Marine Engine Excellence</h3><p>Sierra's reputation was built on delivering precision-engineered internal engine components and drive system parts that meet or exceed OEM specifications. Their <a href="/7570-sierra-engine-gasket-set-5404">engine gasket sets</a> provide critical sealing solutions for inboard and outboard motors, while their <a href="/7570-sierra-engine-complete-assembly-15341">engine complete assemblies</a> offer comprehensive replacement options for major overhauls. Each component undergoes rigorous testing to ensure reliability in demanding marine conditions, from corrosion resistance to temperature cycling performance.</p><h3>Instrumentation and Monitoring Systems</h3><p>Accurate instrumentation is essential for boat operators to monitor engine health and prevent costly breakdowns on the water. Sierra's comprehensive line of <a href="/7570-sierra-gauges-200483">gauges</a> includes everything from fuel pressure and temperature indicators to voltmeters and trim gauges, all designed with marine-grade materials that withstand vibration, moisture, and UV exposure. Their <a href="/7570-sierra-tachometer-gauge-1488">tachometer gauges</a> deliver precise RPM readings critical for optimizing engine performance and fuel efficiency. Supporting these instruments, Sierra's <a href="/7570-sierra-gauge-resistor-47908">gauge resistors</a> ensure proper signal conditioning and accurate readings across various sensor types and engine configurations.</p><h3>Expanded Product Portfolio</h3><p>In 2022, Sierra significantly broadened its scope beyond traditional marine engine parts to encompass a wider range of boating accessories and even outdoor power equipment components. This strategic expansion brought established marine brands like Shields and Moeller under the Sierra umbrella, creating a one-stop resource for marine maintenance and replacement parts. The company now offers fuel systems, electrical components, battery charging solutions, and NMEA electronics alongside their traditional engine parts lineup.</p><h3>Quality Backed by Industry-Leading Warranties</h3><p>What sets Sierra apart in the crowded aftermarket marine parts market is their commitment to standing behind every component they manufacture. Their warranty coverage extends beyond simple part replacement—it includes shop labor, haul-out fees, towing charges, and related incidental costs should a warrantied part fail. This comprehensive protection reflects the company's confidence in their manufacturing processes and quality control standards. For boat owners facing repairs far from shore or mechanics working on customer vessels, this peace of mind is invaluable. Whether you're maintaining an outboard motor, rebuilding an inboard engine, or upgrading your boat's instrumentation, Sierra's decades of marine industry experience and commitment to quality make them a reliable choice for keeping your vessel running at peak performance.</p>

Part Number

18-6406
08/03/2036 9:32 AM
Sale Price

$132.79

In Stock (10+)

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Usually delivered within 2 days

free shipping

FREE SHIPPING

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No Hassle Returns

No Hassle Returns

Live-in-stock inventory

Live-in-stock inventory

Fitment guaranteed

Fitment guaranteed

Product Details

The Sierra 18-6406 is a GKN-style universal joint assembly designed as a direct replacement for Mercruiser sterndrive systems. This u-joint connects drive shaft rods whose axes are inclined at an angle to each other, transmitting rotary motion efficiently between components.

Key Features:

  • GKN new style design with external snap ring clips for secure installation
  • Direct replacement for Mercruiser OEM part numbers 865496A01 and 865493A01
  • Compatible with Alpha I Gen II sterndrives (serial number 0L949779 and up)
  • Fits Bravo sterndrives (serial number 0M111208 and up)
  • Suitable for Mercruiser Vazer applications
  • Precision-engineered for reliable performance in marine environments

This replacement u-joint assembly is an essential component for maintaining proper drive shaft operation in your Mercruiser sterndrive system. The external clip design provides easier installation and service compared to older internal clip styles.

Products specifications

Replaces

865496A01, 865493A01

You had the part's in which I was looking for The only hang up was trying to match all parts for the sizes that would fit together

Very easy to navigate and great pricing!

Smooth. Would do business again

Better price than going direct to the manufacturer.

Fantastic! Will definitely do business in future!

Good so far

thanks

Easy shopping, however the confirmation from the warehouse and then the shipment to my home, took a week. For an overall product purchase it's fine, but if you have your car broken and you are waiting for the part, the waiting time is terrible.

quick and easy

so far so good

Installed a 5th wheel hitch in a F150 with a 5 1/2' bed. Autoplicity had the Sidewinder hitch I needed to put the swivel under the camper insead of at the hitch,also at a lower price than competitors with extremly reasonable shipping $14.38. I Placed the order on a Friday and the item shipped the same day. Very happy with the product and fast shipping.

Great prices!!

Is the part in stock or on back order

Your website is very easy to use and I love the fact that I could pay through Amazon.

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My shopping experience has been great...it was very easy to find the part I was looking for.

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