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Sierra 18-99536 MerCruiser Lower Unit Gear Lube Fill Tube Adapter 551-334B

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

18-99536
08/05/2036 6:38 PM
Sale Price

$29.40

2 left at this price

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Usually delivered within 2 days

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Fitment guaranteed

Product Details

The Sierra 18-99536 is a lower unit gear lube fill tube adapter (CDI part number 551-334B) designed specifically for use with MerCruiser sterndrive and outdrive lower units. This adapter connects to the 551-33-1 gearcase filler system, enabling clean, controlled lower unit gear oil changes on MerCruiser-equipped vessels.

Key Features:

  • Purpose-built adapter for MerCruiser sterndrive and outdrive lower units
  • Compatible with Bravo lower unit and Verado lower unit applications
  • Designed for use with the CDI/Sierra 551-33-1 gearcase filler system
  • Also compatible with 551-34PV and 551-34HA gearcase filler assemblies
  • Sold separately from standard gearcase filler kits, which do not include MerCruiser outdrive adapter

Cross-Reference Part Numbers:

  • CDI Electronics: 551-334B
  • Sierra: 18-99536

This adapter is an essential tool for marine technicians and boat owners performing routine lower unit gear lube maintenance on MerCruiser sterndrives. Proper gear lube service helps extend the life of seals, bearings, and gears within the lower unit.

I paid a little extra for the fast delivery but it was worth it. I got it quickly and it worked great

Fast checkout

Quick &amp;amp;amp; easy

Goo

Cheapest price, found quickly on google, and shipped/delivered extremely quickly!

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