21704781 Gear Ring | Genuine Volvo Penta Part

🔧 Product Description

Starter ring gear fitted to Volvo Penta TAD8 SAE3/Allison flywheel assemblies. It provides the hardened external teeth engaged by the starter pinion and is installed by controlled heating and shrink fitting.

🚤 Compatibility

Typically suits:

• Volvo Penta TAD840GE
• Volvo Penta TAD552VE
• Volvo Penta TAD853VE
• Volvo Penta TAD880-84VE
• Volvo Penta TAD580-83VE
• Volvo Penta TAD570-72VE
• Volvo Penta TAD570-71VE-B
• Volvo Penta TAD550-51VE
• Volvo Penta TAD540-42VE
• Volvo Penta TAD840-43VE
• Volvo Penta TAD850-52VE
• Volvo Penta TAD870-73VE
• Volvo Penta TADH880-84VE

• Engine Family: TAD, TADH

⚙️ Key Features

• Genuine Volvo Penta machined rotating component
• Factory tooth/groove geometry
• Correct diameter, offset and mounting interface
• Designed for the original bearing or belt load
• Serial-specific ratio or application
• Engine type: 7.7-litre inline-six turbocharged diesel

🔌 Function

Provides the hardened gear teeth engaged by the starter motor to crank the engine.

⚠️ Common Signs of Failure

• Chipped or rounded starter teeth
• Loose ring gear
• Cracking after incorrect installation
• Starter grinding
• Uneven wear at recurring stop positions

🛠️ Service Notes

• Compare the new ring with the old for tooth count, tooth form and any chamfer before fitting, and confirm it is the ring specified for your unit's serial number
• Clean the seating shoulder or mounting face completely — dirt, burrs or old thread lock will stop the ring seating square and running true
• Where the teeth are chamfered or leaded on one side, fit that side facing the gear or pinion that engages it, so engagement is not fought
• Where the ring is an interference fit, expand it by even, controlled heating using the method and temperature limit given in the workshop manual, seat it fully against its shoulder and let it cool in air; a torch flame or a quench ruins the tooth hardening
• Inspect the meshing gear or starter pinion at the same time and renew it if its teeth are worn or damaged, then check the ring runs true and meshes correctly by hand before power is applied

🔄 Supersession & Cross Reference

Other-Brand OEM Numbers

• VOE21704781

Aftermarket / Verified Equivalents

• Associated flywheel: 21576050 → 23631629

📦 Condition

• Genuine Volvo Penta part
• Brand new
• Supplied in original or equivalent packaging