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Gear Gasket Kit – Fits Volvo Penta AQ120B/AQ125A/AQ140A/AQ145A (Replaces 876393)

Sale price $89.95 Regular price $143.00
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Worry-free returns

You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).

You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).

If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.

Delivery and Shipping

Free standard shipping on all orders under 1 KG

If you have any questions, feel free to email us at info@sierramarines.com, and we’ll get back to you within 20–36 hours.

Product Details

This Gear Gasket Kit is designed for specific Volvo Penta gasoline engines from the 1970s and 1980s, including models AQ120B, AQ125A, AQ140A, and AQ145A. It serves as a direct-fit replacement for gaskets within the engine's transmission and gear housing, ensuring a reliable seal.

It directly replaces Volvo Penta part numbers 876393 and 875423, as well as Orbitrade ORB21433.

  • Installation: Direct replacement for a precise fit.
  • Application: Intended for use on engine transmissions and gear housings.
  • Key Component: Includes the oil pan gasket (reference 859159) for engines with a 79mm bore.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket suppliers.

Brand Part Number
Volvo Penta 876393
Volvo Penta 875423
Volvo Penta 875588
Orbitrade ORB21433

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This kit is specifically for certain Volvo Penta gasoline engines.

Brand Model Rated HP Stroke OEM Part No.
Volvo Penta AQ120B 120 4-Stroke 876393, 875423
Volvo Penta AQ125A 125 4-Stroke 876393, 875423
Volvo Penta AQ140A 140 4-Stroke 876393, 875423
Volvo Penta AQ145A 145 4-Stroke 876393, 875423

Technical Specs

Product Type
Gear Gasket Kit
Installation
Direct replacement
Fuel Type
Gasoline
Dimensions
55.3cm L x 25.0cm W x 3.3cm H
Other Technical Attributes
For engine transmissions/gear housings
Warranty
Manufacturer dependent; typically 1 year against defects

What’s in the Box

  • 1 x Gear Gasket Kit (876393)
  • Includes oil pan gasket with reference 859159 for engines with 79mm bore

Installation Notes

  1. Disconnect the battery terminals and safely drain engine oil and coolant as required.
  2. Remove any components obstructing access to the gear housing assembly.
  3. Carefully detach the housing, taking note of bolt locations.
  4. Remove the old gaskets completely. Thoroughly clean and degrease all mating surfaces to ensure they are smooth and free of old material.
  5. Position the new gaskets correctly, ensuring all bolt holes and passages align perfectly. Do not use sealant unless specified by your engine's service manual.
  6. Reinstall the gear housing, tightening bolts in a star or crisscross pattern to the manufacturer’s recommended torque specifications.
  7. Reassemble all previously removed components.
  8. Refill the engine with fresh oil and coolant. Start the engine and carefully inspect for any leaks around the newly sealed area.

Troubleshooting & FAQ

How do I know if this kit fits my specific engine?

This kit is for Volvo Penta models AQ120B, AQ125A, AQ140A, and AQ145A. The best way to ensure a match is to cross-reference your existing part number with those listed in the Part Number Matrix or verify your engine model in the compatibility table.

Is this a complete engine overhaul gasket kit?

This is a gear gasket kit, sometimes referred to as a conversion gasket set or oil pan gasket set. It contains the primary gaskets for the gear housing, but it is not a full engine overhaul set. Please review the 'What's in the Box' section to see key included components.

What are the signs of a failing gear housing gasket?

Common symptoms include visible oil leaks from the gear housing, contaminated or milky-looking engine oil (indicating fluid mixing), or potential overheating issues. A visual inspection for residue or active drips is the first step in diagnosis.

Should I use sealant with these gaskets?

In most cases, these gaskets are designed to be installed dry on clean, smooth surfaces. However, always consult your engine's official service manual, as it may recommend a thin layer of a specific sealant in certain locations.

What is the difference between an OEM part and an aftermarket part?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

How much is shipping and how fast will I get my order?

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

What is your warranty and return policy?

Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.

Safety & Important Info

  • Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
  • This is an aftermarket replacement, not an OEM component.
  • Professional installation is recommended for safety and performance.

About Sea Sierra

  • Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
  • Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
  • Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.

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