3979035 Gear | Genuine Volvo Penta Part

🔧 Product Description

Genuine Volvo Penta gear from the Marine Propulsion group, weighing 1.078 kg and listed for 4 applications across the THD and DH series. It supersedes part number 425996.

🚤 Compatibility

Typically suits:

• Volvo Penta THD102KB
• Volvo Penta THD102KD
• Volvo Penta THD102K-KB
• Volvo Penta DH10A

• Engine Family: THD, DH

⚙️ Key Features

• 1.078 kg
• Supersedes 425996
• 4 applications across the THD and DH series
• Marine Propulsion group

🔌 Function

Transmits drive from one shaft to another through meshing teeth, setting the speed and torque relationship between them.

⚠️ Common Signs of Failure

• Whine or growl that changes with load
• Teeth chipped, pitted or worn to a point
• Metal glitter in the oil or on the drain magnet
• Backlash felt to be excessive when the drive is rocked
• Bore or keyway worn so the gear moves on its shaft

🛠️ Service Notes

• Inspect the meshing gear and the bearings at the same time — a damaged tooth flank rarely happens alone
• Renew the oil and clean the housing before reassembly so no debris is carried over

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 3979035 → Supersedes 425996

OEM / Related Numbers

• 425996 earlier number superseded by this part

📦 Condition

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