Volvo Penta 21827365 Shaft Coupling – 25mm Clamp-Type Inboard
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Volvo Penta 21827365 is a genuine OEM clamp-type propeller shaft coupling for 25 mm shaft diameter inboard driveline installations. This two-piece conic coupling provides central alignment and strong torsional hold without shaft damage, and is designed for installation without tapering or keyway cutting.
Part Information
- Part Number: 21827365
- Brand: Volvo Penta
- Official Product Type: Propeller Shaft Coupling (Clamp-Type, OEM)
- Supersedes: 827924, 827925
- Replaced By: No current supersession — 21827365 is the active OEM number
Dimensions & Specifications
- Shaft Diameter: 25 mm
- Length: ~63 mm
- Diameter: ~102 mm
- Weight: ~3.1 kg
- Required Shaft Tolerance: h9 (0 to −0.052 mm)
- Design: Two-piece conic, clamp-type — no taper machining or keyway required
Compatible Applications
- Volvo Penta D1 engines with MS10 gearbox
- Volvo Penta D1 engines with MS15 gearbox
Fitment can vary by engine version, gearbox, shaft diameter, and driveline configuration. Always confirm part number 21827365 against your exact engine serial number, gearbox model, and shaft size before ordering — especially on vessels with prior shaft, gearbox, or coupling changes.
When to Replace
Replace this coupling when you notice fretting, distortion, loosening, corrosion, vibration-related wear, or damage from driveline misalignment. It is also the correct replacement part when rebuilding or upgrading a driveline where the shaft diameter and gearbox match this specification.
Installation Notes
Proper shaft preparation, correct shaft tolerance (h9), and careful driveline alignment are essential during installation. The two-piece conic design simplifies the process by eliminating taper machining and keyway cutting, but the shaft must still be within the specified tolerance range for the coupling to seat and hold correctly.
Alternate & Superseded Part Numbers
Earlier part numbers 827924 and 827925 have been updated to 21827365. Use 21827365 as the current OEM ordering number.
Parts Desk Insights
Shaft couplings are a common source of driveline vibration complaints. The most frequent issue is ordering by engine model alone without confirming the shaft diameter — a near-match coupling that is slightly off on shaft size will not seat correctly and can cause alignment problems or premature wear. Best practice is to verify the shaft diameter and gearbox model directly before ordering. This part is best suited for D1 inboard driveline rebuilds and coupling replacements where the original 25 mm clamp-type specification applies.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.