3GM30F transmission oil

[MikePz]

Well, I sucked out 350ml of oil, and put 350 ml back in and it's on the line on the DS.

My manual has wriiten in ink that the engine is a 3gm20??? How can I tell for sure which engine I have? I've been told by the surveyor and my mechanic it's a 3GM30F!

[MikePz]

I have another question for you, since you seem to be very knowlegable! I have a vibration problem (intermitent) when I put my engine in gear and begin to apply power. The entire engine jumps around on its motor mounts, but once I accelerate to about 3 grand it stops and runs smooth! The shaft is true, the prop is balanced, new cutlass bearing, engine has been bled, what else could it possibly be???

[pcmm]

Originally Posted by a64pilot

I change mine with the engine oil every 100 hours, it's less than a quart on mine and too easy to do.
All it is I believe is a lubricant for the bearing and clutch packs, I don't think there is a pump or any hydraulics, so in truth it could go for years and hundreds of hours before getting so much wear material in it it needed changing, look at how often the average guy changes the automatic transmission fluid in their automobile for example, but to me it's just too easy to change to not change it.

Lol, correct, they're splash lubricated, just like a regular manual transmission in a car! My current car has a manual transmission and there is no replacement interval in the manual!!! I swap it out at 150,000km just for good measure. unless you have an oil cooler in the trans (like the KM4A or KWB21) then you cam pretty much leave it long term. If you have an oil cooler built in I would change it with the engine oil, that way you can check for any water leaks in the cooler.

[pcmm]

Originally Posted by MikePz

I have another question for you, since you seem to be very knowlegable! I have a vibration problem (intermitent) when I put my engine in gear and begin to apply power. The entire engine jumps around on its motor mounts, but once I accelerate to about 3 grand it stops and runs smooth! The shaft is true, the prop is balanced, new cutlass bearing, engine has been bled, what else could it possibly be???

Have you checked for a deteriorated motor mount? sometimes the rubber seperates from the steel on the mounts. That would account for the "jumping"

[MikePz]

New motor mounts 2 yrs old!

[pcmm]

Originally Posted by MikePz

New motor mounts 2 yrs old!

Doesn't really mean anything. Did the problem just start? or has it been ongoing for 2years? you could have the wrong strength mount, or one of them could have become damaged.

[MikePz]

Problem was happening before new motor mounts, according to the Yanmar mechanic these are the right ones for this engine!

[a64pilot]

In my boat manual there is a statement that says there are some RPM's that will cause driveline vibration. Avoid continuous operation at those RPM's.
In other words there are RPM's that will correspond to the natural resonance frequency of the driveline, avoid those.

You should have a data plate on your engine that tells you it's serial number and model number, both can sometimes be needed when ordering parts

Not saying you don't have a problem, but if you have checked everything, you may not.

On my IP, engine alignment is very critical, it has to be dead on perfect, and still I get some vibration.

[MikePz]

Are you an A6 driver?

[Badsanta]

Yes, I had someone at WM tell me that all yanmars took ATF. but I checked the book. 3gm30f takes motor oil.

There is no 3gm20.

[a64pilot]

I retired in 02 as an AH-64 driver.
Some Kanzaki if I spelled that right transmissions do take ATF, mine does, many take motor oil, you do have to be careful as I think if it's supposed to have motor oil and you put in ATF, if may not be properly lubricated and if you put motor oil where ATF is supposed to be, it may slip?
Mine has clutch packs, many have cones, there may be a correlation that clutch packs take ATF and cones take motor oil, but I don't know.


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[MikePz]

An Army Pilot , Yee Haaaa! I'm SF, retired now, but I do like them helicopter pilots! Although, UH1H's and Cobras is all we had!

[MikePz]

Are you on the IPOYA site also!

[Schrewsburyduo]

F means fresh water. So 2gm20 is raw water coiled. 2gm20f means fresh water cooled. I believe all the gm series have engine oil for transmission oil. Call a dealer with your serial number before putting any atf as it will most likely ruin the transmission. I'm not sure there's a 3gm30 I think all the three cylinders from this series were f fresh water cooled.

I have the 2gm20fF and the oil is also very hard to see in the transmission. The regular oil for the motor gets black quickly because of the combustion. Even after you just filled up with new oil and ran it for a couple of minutes it turns dark and is easy to see the level in the dipstick. However in the transmission it's more difficult. I dry the stick really well with cloth and paper towel. Then take a good look at the stick. Then pop it in and don't screw it. Then take it out and look at the bottom. If you can see a bit of teardrop on the stick all the way to the line then that's the right amount. If the teardrop is above the line then you have too much. If you can't see a little tear bulge of liquid at all then you don't have enough oil.

It's worth checking the transmission oil every year but not worth changing every year as it hardly uses itself up.
My 2 cents.


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[Schrewsburyduo]

2gm means two cylinder. 3gm is three cylinder. Easy to find. Look for how any fuel injectors you have. The later model was then called 2gm20 ( bump up to 20 hp for the original 16 I think) and 3gm30. For 30 hp for the 3 cylinder. There is no such thing as 3gm20 or 2gm30.

Yes pls use motor oil. No atf.
Everything that has been said is true. You can get a basic reading in the gear dipstick if you really dry it out.... and use your iPhone flashlight to see if there is any liquid at all on the stick. This is what i do. I do it once every 2-3 yrs. you red to use a small pump to suck the oil out. If stuck use an ear wax remover those bulb pumps....