Volvo Penta Gear Housing – OEM Part 21658888

Volvo Penta Gear Housing – OEM Part 21658888

Part Number: 21658888
Brand: Volvo Penta
System: Sterndrive / Lower Drive Assembly
Engine Family: Volvo Penta sterndrive systems (confirm by drive model and serial number)

This is the genuine OEM gear housing for select Volvo Penta sterndrive assemblies. The gear housing is the structural core of the lower drive unit — it houses the drive gears, bearings, and seals that transfer power from the engine to the propeller. At $11,800, this is one of the highest-value components in the drive system. Fitment must be confirmed by drive model and serial number before ordering.

Compatible Applications

• Volvo Penta sterndrive systems — specific drive model confirmed by serial number
• Verify fitment using your drive model designation and serial number on the drive ID plate
• Cross-reference against the Volvo Penta parts diagram for your drive assembly before ordering

Technical Specifications

• Part Number: 21658888
• Type: Gear housing (lower drive unit)
• System: Sterndrive lower drive assembly
• Construction: OEM marine-grade
• Weight: Approx. 3 kg (estimated — confirm with freight carrier for shipping)

Parts Desk Insights

Gear housing replacements are most commonly needed after a significant impact — striking a submerged object, a hard grounding, or a propeller strike that transmits shock load into the housing. Cracks or fractures in the housing are not always immediately visible; overheating, gear noise, or sudden oil loss are often the first signs. This is also ordered during full drive rebuilds on high-hour units where the housing shows wear at bearing bores or seal surfaces. Because this is a high-value structural component, we strongly recommend confirming your drive serial number and consulting the Volvo Penta parts diagram before ordering. A misidentified housing is a costly mistake.

Service Interval

Inspect the gear housing during every major drive service. Replace immediately if cracking, fracture, bearing bore wear, or seal surface damage is found. Gear lube should be changed annually or every 100 hours — contaminated or milky gear lube is an early indicator of seal or housing failure.

Signs This Part Needs Replacement

• Visible cracks or fractures in the housing body
• Gear noise or vibration under load
• Sudden gear lube loss or milky/contaminated lube
• Bearing bore wear or damaged seal surfaces
• Impact damage from grounding or propeller strike
• Full drive rebuild on high-hour unit

Technical FAQ

Q: Can I rebuild the existing housing instead of replacing it?
In some cases, yes — if damage is limited to seals and bearings, a rebuild kit may be sufficient. However, if the housing itself is cracked or the bearing bores are worn beyond spec, replacement is required. A qualified marine technician should assess the housing before ordering.

Q: How do I confirm this is the right housing for my drive?
Use your drive model designation and serial number, then cross-reference with the Volvo Penta parts diagram for your specific drive. Serial number breaks are common on Volvo Penta drives — the same drive model may use different housings across production runs.

Q: What else should I replace at the same time?
When replacing the gear housing, plan to replace all seals, O-rings, bearings, and thrust plates. Gear lube should also be refreshed. See related parts below.

Related Parts

• Volvo Penta Gear Housing 22227295
• Volvo Penta Gear Housing 3842842
• Volvo Penta Upper Gear Core 3804451
• Volvo Penta Starboard Thrust Plate – Upper Gear Housing 3589524
• Volvo Penta Thrust Plate – Upper Gear Housing 3589522
• Volvo Penta Lower Gear Housing O-Ring SX-A DPS 3889786
• Volvo Penta Lower Gear Housing O-Ring 3889784
• Volvo Penta Gasket Kit 3888917
• Volvo Penta Transmission Oil 80W-90 GL-5 1141676