Yanmar Marine Transmission Oil Pressure Low
The YANMAR-TRANSMISSION-OIL-PRESSURE (Yanmar) diesel fault code means: Yanmar Marine Transmission Oil Pressure Low. This is a critical severity code.
- Keep driving?
- No — stop driving
- DIY difficulty
- advanced
- Estimated cost
- $10-$4,500
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Common Symptoms
- No shift, slip
- Transmission alarm
Probable Causes (Ranked by Likelihood)
- Low ATF in Kanzaki / ZF marine gear Likely
- Worn clutch packs Possible
- Failed shift cable sticking between positions Possible
Frequently Asked Questions
What is Yanmar code MARINE-TRANS?
Yanmar MARINE-TRANS: Yanmar Marine Transmission Oil Pressure Low. This code is reported on Yanmar equipment running the described engine family.
Can I keep working with Yanmar code MARINE-TRANS?
Do not continue operating. Risk of engine damage or unsafe shutdown.
How much does Yanmar MARINE-TRANS cost to fix?
Estimated repair cost: $10-$4,500. Off-road diesel shop labor runs $125-$175/hr in 2026. Dealer diagnostic software (Yanmar SmartAssist / YDT) is usually required.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
Check ATF level at dipstick (engine running, in neutral).
Verify shift cable reaches full travel at both helm and trans.
Pressure-test clutch circuits.
Commonly Affected Vehicles
- Hunter / Beneteau / Catalina sailboats with Yanmar 3JH / 4JH
- Trawlers and sport fishing boats with Yanmar 6LY / 6LF series
- Sailboat auxiliaries with Yanmar 2YM / 3YM / 3JH5 diesels
- Commercial fishing vessels with Yanmar 6LY3-UTP
- Yachts with Yanmar 6LY400 / 6LY440 / 8LV common-rail marine diesels
- Workboats with Yanmar 4LV / 4JH series marine propulsion
- Ski boats and express cruisers with Yanmar marine diesels
- Tenders and RIBs with Yanmar 3YM20 / 3YM30 sailboat aux
- Island-hopper ferries with Yanmar 6AYM / 6HYM commercial series
- Tug boats and small workboats with Yanmar 6HAL-HTP / 6HYM
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