Volvo Penta Lower Gear Housing O-Ring SX-A DPS - 3889786
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The Volvo Penta 3889786 Lower Gear Housing O-Ring is a genuine OEM molded sealing ring used in compatible Volvo Penta sterndrive lower gear housing assemblies. This static fluid seal helps protect the gearcase joint from water intrusion and helps retain gear lubricant where the lower gear unit and related housing components mate.
It is commonly serviced alongside companion sealing parts such as Volvo Penta 3889784 when the lower gear housing is separated, resealed, pressure-tested, or repaired.
Key Features
- Genuine Volvo Penta lower gear housing sealing O-ring.
- Volvo Penta part number: 3889786.
- Replaces legacy Volvo Penta part number: 3841968.
- Component type: molded O-ring / drive housing gasket.
- Designed for compatible Volvo Penta sterndrive lower gear unit sealing applications.
- Helps prevent water entry into internal gear chambers.
- Helps retain marine gear lubricant at the housing joint.
- Low-profile elastomeric static seal.
- Used in lower unit reseal, prop shaft service, and gearcase pressure-integrity repairs.
- Related companion seal: Volvo Penta 3889784.
Drive Compatibility
Common application context includes Volvo Penta sterndrive lower gear housing assemblies where 3889786 or superseded number 3841968 is listed in the parts diagram, including:
- Volvo Penta SX-A sterndrive applications where specified.
- Volvo Penta DPS-A sterndrive applications where specified.
- Volvo Penta DPS-B sterndrive applications where specified.
- OXi configuration applications where the parts diagram calls for this seal.
- Lower gear housing split / reseal service.
- Propeller shaft assembly service.
- Gearcase pressure-test and vacuum-test repairs.
Use this seal only where the exact drive model, serial number, gear housing style, and Volvo Penta parts diagram confirm 3889786.
Serial Number Fitment Notice
Confirm fitment by Volvo Penta drive model, serial number, gear housing revision, diagram location, and related sealing components before ordering. SX-A, DPS-A, DPS-B, and OXi drive configurations can vary by production range, gear housing design, and previous service history.
If performing a complete lower unit reseal, confirm whether the job also requires the complete seal bundle, such as Volvo Penta lower unit gasket kit references 3888821 or 3888822, where applicable.
When This Part Needs Replacement
Replace this O-ring whenever the lower gear housing joint is opened, during a lower unit split, after prop shaft reseal work, after gearcase impact repair, or when pressure/vacuum testing indicates leakage. Replacement is also recommended if the seal is flattened, cut, swollen, hardened, twisted, pinched, contaminated, or exposed during disassembly.
Milky gear oil, gear lube loss, pressure-test failure, or water intrusion during drain inspection are all signs that the gearcase sealing system should be inspected and serviced.
Installation Notes
Clean the aluminum mating surfaces and O-ring groove thoroughly before installation. Remove salt crust, old gasket residue, gear oil, sealant, grit, and corrosion from the groove and housing faces. A small piece of debris or a twisted O-ring can create a leak path after reassembly.
Lightly lubricate the new O-ring with clean marine gear oil before seating it in the groove. Make sure it lies flat without stretching, rolling, or pinching. Align the gear housing carefully during assembly and tighten fasteners according to the Volvo Penta service procedure. After reassembly, pressure-test and vacuum-test the gearcase before refilling with lubricant.
Alternate / Superseded Part Numbers
- Volvo Penta 3889786 — current supplied part number
- Volvo Penta 3841968 — legacy / superseded reference
- 3889786 O-Ring — common catalog description
- Lower Gear Housing Gasket — common application description
- Volvo Penta 3889784 — related companion lower gear housing seal
- Volvo Penta 3888821 — related lower unit gasket kit reference; verify by drive model
- Volvo Penta 3888822 — related lower unit repair kit reference; verify by drive model
Parts Desk Insight
This seal works as part of the lower gear housing sealing system, not as an isolated component. When one O-ring has been disturbed, the surrounding seals should be inspected at the same time. A clean groove, correct seal placement, and a successful pressure/vacuum test are the best safeguards against water-contaminated gear oil and internal gearcase damage.
Shipping: Ships same or next day for fast Canada wide shipping. ⚓
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.
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