Introduction
Keeping your inboard engine’s transmission oil fresh is vital for smooth performance and avoiding big repairs. This guide walks you through the process step-by-step!
????️ Tools & Materials Needed- Replacement transmission oil (check your manual)
- Oil extraction pump (manual or electric)
- Funnel
- Container for old oil
- Clean rags
- Wrench (if needed for drain plug)
- New transmission oil filter (if applicable)
???? Step-by-Step Process
1. Warm Up the Engine
Run the engine for a few minutes to warm the oil (optional, but it helps with extraction).
2. Locate the Fill and Drain Points
Check your manual for the dipstick, fill port, and drain plug. Some use an extraction pump via the dipstick tube.
3. Extract the Old Oil
- With a drain plug, place a container underneath and remove it to drain.
- Without a plug, use an extraction pump through the dipstick tube.
4. Check for Contaminants
Look for metal shavings, water, or a burnt smell in the old oil. Issues may need a deeper check.
5. Replace the Oil Filter (If Required)
Some transmissions have a filter—see your manual for replacement details.
6. Refill with New Oil
- Use a funnel to add the right oil type and amount.
- Don’t overfill—check the dipstick level.
- Get your oil here
7. Run & Check Levels
Idle the engine in neutral for a few minutes, then top off the oil if needed.
8. Inspect for Leaks
Check the drain plug and fill cap for any leaks.
9. Dispose of Old Oil
Take used oil to a recycling center for proper disposal.
???? Popular Inboard Marine Gearboxes
Check out these common gearboxes:
- Hurth (ZF)
- Volvo Penta IPS
- Twin Disc
- PRM
- Technodrive (TMC)
- Borg Warner Velvet Drive
- Yanmar
- Masson Marine
- Check your manual for specific instructions and oil type.
- Inspect oil regularly for discoloration or debris.
- If gears slip or make noise, get a transmission check.
Follow these steps to keep your transmission running strong for years!
???? Oil Types by Gearbox
- Kanzaki (Yanmar)
- KBW10E ATF Oil 0.7 Liters
- KBW20 ATF Oil 1.2 Liters
- KBW20-1 ATF Oil 1.2 Liters
- KBW21 ATF Oil 1.2 Liters
- KM2P Same oil as engine 0.3 Liters
- KM3A-1 Same oil as engine 0.45 Liters
- KM3P Same oil as engine 0.35 Liters
- KM3P4 Same oil as engine 0.35 Liters
- KM35P Same oil as engine
- KM35A Same oil as engine
- KM35A2 Same oil as engine
- KM3V SEA 30 Motor Oil 0.8 Liters
- KM4A SEA 30 Motor Oil or same as engine 1.3 Liters
- KM4A1 SEA 30 Motor Oil or same as engine 1.3 Liters
- ZF 30 M ATF
- KM5A SEA 30HD Oil 2.1 Liters
- KMH4A Hydraulic Oil 2.0 Liters
- KMH6A Hydraulic Oil 4.0 Liters
- KMH6A1 Hydraulic Oil 4.0 Liters
- SD20 SAE 80W90 Gear Oil (except GM1 Engine) 2.2 Liters
- SD31 SAE 80W90 Gear Oil (except GM1 Engine) 2.2 Liters
- SD40 Quicksilver High Performance Gear Lube 1.8+ Liters
- SD40-T Quicksilver High Performance Gear Lube 2.1+ Liters
- YX-70 Hydraulic Oil 5.0 Liters
- Bukh
- Bukh Saildrive DV10LSME Hypoid Gear Oil SEA90 or SEA80W90 0.4 Liters
- Bukh Saildrive DV10 Hypoid Gear Oil SEA90 or SEA15W40 3.3 Liters
- Bukh Saildrive DV20 Hypoid Gear Oil SEA90 or SEA15W40 3.3 Liters
- Bukh Saildrive DV24 Hypoid Gear Oil SEA90 or SEA15W40 3.3 Liters
- Bukh Saildrive DV36 Hypoid Gear Oil SEA90 or SEA15W40 3.3 Liters
- Bukh Saildrive DV48 Hypoid Gear Oil SEA90 or SEA15W40 3.3 Liters
- Hurth
- Hurth HBW 5 ATF Oil 0.35 Liters
- Hurth HBW 10 ATF Oil 0.55 Liters
- Hurth HBW 20 ATF Oil 0.75 Liters
- Hurth HBW 35 ATF Oil 0.30 Liters
- Hurth HBW 40 ATF Oil 0.30 Liters
- Hurth HBW 50 ATF Oil 0.30 Liters
- Hurth HBW 100 ATF Oil 0.35 Liters
- Hurth HBW 125 ATF Oil 0.55 Liters
- Hurth HBW 150A ATF Oil 0.5 Liters
- Hurth HBW 150V ATF Oil 1.0 Liters
- Hurth HBW 250 ATF Oil 0.75 Liters
- Hurth HSW ATF Oil 3.5 Liters
Always check your manual for the right oil type and amount!
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