91-56775T Aftermarket Mercruiser Drive Shaft Adaptor | Sawley's Select Marine Parts

🔧 Product Description

Aftermarket Mercury/MerCruiser 13-spline driveshaft holding adaptor - Part Number: 91-56775T

A 13-spline driveshaft adaptor that provides a hex or wrenching surface for rotating and holding the driveshaft during pinion-gear installation, bearing-preload checks and gear-backlash setup.

⚙️ Key Features

• Engages a 13-spline Mercury/MerCruiser driveshaft

• Provides an external wrenching surface

• Allows the shaft to be held while the pinion nut is tightened

• Supports backlash and bearing-preload measurements

• Cross-references to Sierra 18-9854, Mallory 9-79809 and GLM 90220

🔄 Supersession & Cross Reference

OEM Supersession Chain:

• 91-56775T → Supersedes 91-56775

OEM / Related Numbers:

• 91-56775T

• 91-56775

• Sierra 18-9854

• Mallory 9-79809

• GLM 90220

Aftermarket / Verified Equivalents:

• Sierra: 18-9854

• Mallory: 9-79809

• GLM: 90220

🚤 Compatibility

Commonly used on:

• Mercury 13-spline outboard gearcases and MerCruiser Alpha-family drives

Typically suits:

• Drive / engine models:

• MerCruiser Vazer

• MerCruiser MC-I

• MerCruiser R and MR

• MerCruiser Alpha One

• MerCruiser Alpha One Gen II

• Mercury outboard gearcases with a compatible 13-spline driveshaft

• Spline Count: 13

• Tool Type: Driveshaft holding and turning adaptor

🔌 Function

The adaptor slides over the driveshaft splines and converts the shaft end into a wrenchable surface so it can be rotated or locked during gear setup and pinion installation.

Common signs the tool or component is required:

• The specified component cannot be removed or installed without damaging the surrounding housing

• A standard puller, wrench or improvised tool cannot engage the factory service points correctly

• Accurate bearing, gear, cable or pulley positioning is required during assembly

• Corrosion, press fit or retained components require controlled service force

• The applicable workshop procedure calls for the listed OEM special-tool number

📦 Condition

• Brand new aftermarket replacement tool or service component

• New and unused

• Supplied in manufacturer or equivalent protective packaging