Lower Unit Gearcase Seal Kit for Suzuki DT40C, DF40/DF50/DF60 & Johnson/Evinrude 40-50HP Outboards
Lower Unit Gearcase Seal Kit for Suzuki DT40C, DF40/DF50/DF60 & Johnson/Evinrude 40-50HP Outboards is backordered and will ship as soon as it is back in stock.
Worry-free returns
Worry-free returns
Shop with confidence. If you’re not completely satisfied, eligible items may be returned within the return window, provided they are unused and in original packaging.
If the return is due to our error or a defective item, we’ll make it right.
Please contact us before returning any item.
Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
International delivery times may vary due to customs processing.
Tracking information will be provided once your order ships.
Lower Unit Gearcase Seal Kit for Suzuki DT40C, DF40/DF50/DF60 &...
Lower Unit Gearcase Seal Kit for Suzuki DT40C, DF40/DF50/DF60 & Johnson/Evinrude 40-50HP Outboards is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket Lower Unit Gearcase Seal Kit is designed to service the lower unit on selected Suzuki and Johnson/Evinrude outboard motors. It supplies replacement seals, O-rings, gaskets, a bellows and related gearcase service hardware for the applications listed below.
The kit is listed for Suzuki DT40C, DF40, DF50, DF60, DF40A, DF50A and DF60A outboards, as well as selected Johnson/Evinrude 40HP and 50HP 4-stroke models. Always compare the engine model, year and existing part number before ordering.
- Aftermarket replacement lower unit and gearcase seal kit.
- Includes transmission-shaft and propeller-shaft oil seals, gearcase O-rings, drain gaskets, a water-pump gasket and bellows.
- Designed to help restore sealing at service points in the lower unit and reduce the risk of water intrusion or lubricant leakage when correctly installed.
- Professional installation is recommended because lower-unit disassembly, correct torque procedures and pressure testing may be required.
OEM and Aftermarket Reference Numbers
These numbers are provided as reference points for identifying the correct application. They do not expand the stated fitment beyond the models and years shown below.
| Brand or source | Reference number | Type |
|---|---|---|
| Suzuki | 25700-94400 | OEM reference |
| Suzuki | 25700-88L00, 25700-88L01, 25700-88L02, 25700-88L03 | OEM references |
| Evinrude / Johnson / BRP | 5031456 | OEM reference |
| Sierra Marine | 18-8337 | Aftermarket reference |
Engine & Model Compatibility
Fitment is conditional on the complete model and year range. The horsepower, stroke and year conditions below should be considered together.
| Brand | Model | Rated HP | Stroke | Years | Reference numbers |
|---|---|---|---|---|---|
| Suzuki | DT40C | 40 | 2-Stroke | 1984–1998 | 25700-94400 |
| Suzuki | DF40, DF50 | 40, 50 | 4-Stroke | 1999–2011 | 25700-88L00, 25700-88L01, 25700-88L02, 25700-88L03 |
| Suzuki | DF60 | 60 | 4-Stroke | 2010–2011 | 25700-88L00, 25700-88L01, 25700-88L02, 25700-88L03 |
| Suzuki | DF40A, DF50A, DF60A | 40, 50, 60 | 4-Stroke | 2011–2018 | 25700-88L00, 25700-88L01, 25700-88L02, 25700-88L03 |
| Johnson / Evinrude | E40, J40, BJ40 | 40 | 4-Stroke | 1999–2006 | 5031456 |
| Johnson / Evinrude | E50, J50, BJ50 | 50 | 4-Stroke | 1999–2006 | 5031456 |
Technical Specs
- Product Type
- Lower unit / gearcase seal kit
- Construction
- Aftermarket replacement components
- Application
- Selected Suzuki and Johnson/Evinrude outboard lower units
- Installation
- Professional marine-mechanic installation recommended
What's in the Box
One complete lower unit gearcase seal kit containing the following components:
| Component | Quantity | Reference number |
|---|---|---|
| Water-pump gasket | 1 | 17472-96303 |
| Gearcase O-ring | 1 | 55122-94400 / 55122-88L00 |
| Diabolo O-ring | 1 | 09280-75001 |
| Transmission-shaft oil seal | 2 | 09282-17005 |
| Propeller-shaft oil seal | 2 | 09289-22007 |
| Gearcase drain gasket | 3 | 09168-10022 |
| Shift-rod O-ring | 2 | 09280-08005 |
| Shift-rod O-ring | 1 | 09280-11005 |
| Bellows | 1 | 25222-96300 |
Installation Notes
Lower-unit seal replacement is a specialized repair. The typical procedure may involve draining the gear lubricant, removing the propeller and lower-unit components, replacing the specified seals, O-rings, gaskets and bellows, then reassembling with the manufacturer's torque procedures. A pressure test should be performed after assembly to verify that the gearcase is sealed correctly.
Use appropriate marine lubricants and installation tools, and replace damaged hardware or components discovered during disassembly. If the engine model, year or lower-unit configuration does not exactly match the fitment information above, verify compatibility before installation.
Troubleshooting & FAQ
Which Suzuki engines does this kit fit?
The listed Suzuki applications are DT40C models from 1984–1998; DF40 and DF50 models from 1999–2011; DF60 models from 2010–2011; and DF40A, DF50A and DF60A models from 2011–2018. Verify the complete model and year before ordering.
Which Johnson/Evinrude engines does this kit fit?
The listed Johnson/Evinrude applications are E40, J40 and BJ40 40HP 4-stroke models, plus E50, J50 and BJ50 50HP 4-stroke models from 1999–2006.
Is this an OEM kit?
No. This listing is for an aftermarket replacement kit. The OEM and aftermarket reference numbers are supplied for identification and cross-reference purposes.
What are common signs that lower-unit seals need service?
Possible signs include milky or cloudy gear lubricant, water contamination, lubricant around the propeller shaft or driveshaft area, or a pressure-test failure. Inspect the lower unit during routine gear-lubricant service.
Can I replace only one seal?
The kit is intended to renew multiple lower-unit sealing points at the same time. Whether every component must be installed depends on the engine configuration and the repair being performed. Follow the applicable service information for your exact model.
Safety & Important Information
- Verify the complete engine model, horsepower, stroke and year before purchase.
- Do not rely on horsepower alone; lower-unit configurations can vary by model and year.
- Compare the original components and reference numbers before installation.
- Professional installation is recommended for correct disassembly, torque, sealing and pressure testing.
- This is an aftermarket replacement product and is not manufactured by Suzuki, Johnson, Evinrude or BRP.
About Sea Sierra
- Marine Replacement Parts — We supply aftermarket components for practical repair and maintenance applications.
- Application-Focused Listings — Product information is organized around model, year, horsepower and stroke conditions.
- Service-Ready Information — Reference numbers and kit contents are provided to support part identification before installation.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
