Volvo Penta HS25A 2.71 Marine Gearbox
Description
Angled for semi-displacement motor yachts, Volvo Penta HS25A Marine Reduction Transmission packages drop diesel engine revolutions through a 2.71:1 reduction ratio. The driveline unit channels 150 continuous horsepower at 3800 input RPM with hydraulic clutch clamping force. An 8-degree down angle suppresses shaft inclination, optimizing propeller thrust angles on fast coastal motor cruisers.
Cast aluminum forms a stiff transmission housing designed to resist gear deflection under heavy continuous vessel push. Case-hardened 8620 alloy steel helical gears produce silent power conversion with minimal frictional resistance. Multi-disc sintered bronze clutch packs run immersed in pressurized oil for rapid heat removal. External hookups include 7/16-20 JIC pressure gauge taps, oil cooler lines, 1.8 quarts oil volume, and 57 lbs dry weight.
Key Features of Volvo Penta HS25A
Yacht refit shipyards choose to buy Volvo Penta HS25A marine transmission hardware to repower fast semi-displacement motor yachts. This drive train couples straight to Volvo Penta D3 and D4 diesel engines working under strenuous continuous cruising loads.
- An 8-degree down angle allows level engine installation inside low profile salon bilge spaces.
- A 2.71 to 1 reduction ratio permits the installation of broad four-blade propeller wheels on displacement hulls.
- Hydraulic clutch packs squeeze sintered bronze friction plates to prevent slip during sudden engine throttle transitions.
- Precision ground helical gear teeth transfer up to 210 lb-ft continuous input torque without surface wear.
- An internal positive displacement oil pump maintains hydraulic line pressure between 230 and 280 PSI.
- External fluid lines route lubricant through a compact oil heat exchanger mounted adjacent to the casing.
- Flexible elastomeric coupling elements absorb cyclic engine crankshaft shock before entering the drive pinion shaft.
Deep Reduction Thermal Ratings
Internal lubrication pumps produce 250 PSI line pressure during high engine load conditions, preventing clutch pack slip while turning large wheel diameters. Sump operating temperatures stabilize between 140°F and 175°F through a high-flow oil heat exchanger rejecting 200 BTU per minute. Rated for 210 lb-ft input torque at 3800 continuous engine RPM, this 2.71:1 reduction mechanism optimizes propeller rotation for heavy cruising crafts. Deep gear ratios lower shaft revolutions to yield steady forward thrust against rough coastal sea swells.
Angled Flange Coupling Geometry
A forged steel companion flange provides a 3.25-inch bolt circle matching four Grade 8 fasteners angled 8 degrees downward. Built-in heavy taper roller bearings take up 10 kilonewtons of shaft propeller thrust. Dialed runout alignment across the companion flange must remain below 0.0025 inches during shaft integration.
Suction Filter Care Protocol
Gear selection takes place via a three-position mechanical control head that engages forward, neutral, and reverse without delay. This reduction gearbox is not built for racing runabouts or lightweight stepped hulls powered by high-speed gasoline engines. Maintenance procedures demand structured upkeep intervals.
- Verify oil level with the dipstick gauge each shift before firing the main diesel engine.
- Extract and clean the magnetic drain plug plus internal oil suction screen every 250 run hours.
- Pump out old transmission oil down to the bottom and install fresh ATF fluid every 12 months.
Certified Transmission Warranty Terms
The manufacturer includes a 2-Year limited warranty protecting marine buyers against casting or gear machining flaws. Crated shipments contain the complete marine gearbox, flexible input coupling plate, oil cooler module with lines, output companion flange, oil dipstick gauge, and factory shop service documentation.
Volvo Penta HS25A 2.71 Marine Gearbox Product Overview
The NEW Volvo Penta HS25A 2.71 Marine Gearbox is designed for vessel owners, marine technicians, shipyards, and repower specialists requiring a dependable transmission solution for compatible inboard marine propulsion systems.
A marine gearbox is an essential drivetrain component that transfers engine power to the propeller while reducing engine speed to match the vessels propulsion requirements. The Volvo Penta HS25A gearbox features a 2.71:1 reduction ratio, helping provide efficient torque delivery and suitable propeller operation when correctly matched with the engine and vessel configuration.
Supplied as a new boxed Volvo Penta marine gearbox, this transmission provides a practical replacement solution for compatible marine propulsion installations.
For customers searching for a Volvo Penta HS25A 2.71 marine gearbox for sale, Volvo Penta transmission replacement, or a reliable inboard gearbox solution, the HS25A provides trusted marine drivetrain performance.
Designed for Inboard Marine Propulsion Systems
The Volvo Penta HS25A 2.71 Marine Gearbox is designed for compatible inboard marine propulsion applications.
Marine gearboxes help deliver engine power to the propeller by providing the correct reduction ratio and torque characteristics required for efficient vessel operation.
This gearbox can be suitable for applications including:
- Sailing yachts
- Recreational boats
- Motor yachts
- Commercial vessels
- Marine repower projects
The correct gearbox selection depends on engine specifications, vessel design, propeller requirements, and operating conditions.
2.71:1 Reduction Ratio Performance
The Volvo Penta HS25A Marine Gearbox features a 2.71:1 reduction ratio.
A reduction gearbox allows the marine engine to operate within its preferred speed range while reducing propeller shaft RPM and increasing available torque. This helps achieve efficient propulsion performance when correctly matched with the vessels engine and propeller system.
The correct gearbox setup should consider:
- Engine horsepower
- Engine RPM
- Engine rotation
- Propeller specifications
- Vessel size
- Intended application
Proper gearbox selection supports smooth operation, efficient propulsion, and long-term drivetrain reliability.
Reliable Solution for Marine Repower Projects
The NEW Volvo Penta HS25A 2.71 Marine Gearbox is a practical option for compatible marine repower projects where an existing transmission requires replacement or a new propulsion system is being installed.
During a repower, the gearbox must be correctly matched with the engine, shaft system, and propeller to ensure proper drivetrain integration.
This gearbox can support:
- Existing gearbox replacement
- Vessel refurbishment
- Engine upgrade projects
- Propulsion system maintenance
- Compatible new installations
Before installation, buyers should confirm gearbox specifications, engine compatibility, mounting requirements, and vessel configuration.
Volvo Penta Marine Transmission Engineering
The Volvo Penta HS25A Gearbox benefits from Volvo Pentas experience developing marine propulsion systems for recreational and professional vessels.
Volvo Penta marine transmissions are designed to provide reliable power transfer, efficient operation, and practical integration with compatible marine engines.
For vessel owners and marine professionals, selecting a Volvo Penta gearbox helps support proper compatibility and dependable propulsion performance.
Installation and Compatibility Considerations
Before purchasing the NEW Volvo Penta HS25A 2.71 Marine Gearbox, buyers should confirm compatibility with their vessel and engine configuration.
Important factors include:
- Engine model
- Engine power output
- Engine rotation
- Reduction ratio requirements
- Shaft alignment
- Propeller specifications
- Mounting arrangement
- Control system compatibility
Professional marine installation is recommended to ensure correct alignment and reliable drivetrain operation.
Worldwide Marine Equipment Supply
The NEW Volvo Penta HS25A 2.71 Marine Gearbox is suitable for customers requiring professional marine transmission supply and international delivery support.
With experience shipping marine engines, transmissions, and spare parts worldwide, this gearbox can support vessel owners, shipyards, marine technicians, and repower specialists requiring dependable Volvo Penta drivetrain components.
Technical Specifications
| Specification | Details |
|---|---|
| Product Name | NEW Volvo Penta HS25A 2.71 Marine Gearbox |
| Manufacturer | Volvo Penta |
| Product Type | Marine gearbox / transmission |
| Condition | New |
| Reduction Ratio | 2.71:1 |
| Application | Inboard marine propulsion |
| Suitable Applications | Sailing yachts, recreational boats, motor yachts, commercial vessels, repower projects |
| Main Function | Engine power transfer and propeller speed reduction |
| Installation | Compatible Volvo Penta marine propulsion systems |
Key Product Details
The NEW Volvo Penta HS25A 2.71 Marine Gearbox is a brand-new boxed Volvo Penta marine transmission designed for compatible inboard propulsion systems.
It features a 2.71:1 reduction ratio to provide efficient engine-to-propeller power transfer.
The gearbox is suitable for marine applications requiring dependable transmission performance, smooth operation, and Volvo Penta drivetrain compatibility.
Before purchase, buyers should verify engine compatibility, shaft requirements, vessel application, and installation specifications.
Frequently Asked Questions
What is the Volvo Penta HS25A 2.71 Marine Gearbox used for
The Volvo Penta HS25A Marine Gearbox is used in compatible inboard propulsion systems to transfer engine power to the propeller while reducing output speed.
What is the reduction ratio of this gearbox
This gearbox features a 2.71:1 reduction ratio.
Is the Volvo Penta HS25A gearbox new
Yes. It is supplied as a brand-new boxed Volvo Penta marine gearbox.
What vessels can use this gearbox
The HS25A can be suitable for compatible sailing yachts, recreational boats, motor yachts, commercial vessels, and marine repower applications.
Can this gearbox be used for a repower project
Yes, it can be used for compatible repower projects when correctly matched with the engine, propeller, and vessel requirements.
Does gearbox compatibility need to be confirmed
Yes. Buyers should confirm engine specifications, RPM, rotation, mounting requirements, shaft details, and vessel application before installation.
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