Yanmar Gearbox Lube Oil Questions

[four winds]

I have the KM3V, vdrive. The manual states the "fully inserted" sentence and the next sentence states to check the level of the clutch case oil without screwing in the dip stick.

I have the same dipstick shown here, with only the one mark near the tip. Using the drain plug then filling with the right amount of oil results in a level indicated on this single mark.

The reason for this unconventional dip stick is because it serves as the breather as well. In operation the level is below the hollow tubular stick allowing it to breath up to the small hole near the cap. But I have yet to try to figure out how it gets from there to outside the case. But it's what the manual says.

[Rapanui]

I would give Marine Power in Burseldon a call. They are the local experts and have always been helpful to answer my naive Yanmar questions.

[Dockhead]

Originally Posted by Rapanui

I would give Marine Power in Burseldon a call. They are the local experts and have always been helpful to answer my naive Yanmar questions.

That's a good idea. This thread is very old and the question long since answered, but for whoever else might be in this area -- the Marine Power guys (a family business) are very knowledgeable and helpful. I buy all my parts from them, and they have worked on my Yanmar from time to time. They also have an office in Portsmouth or Gosport IIRC.

[nicholson31]

Dockhead; yes this thread is old but did you ever get the answer to your original question of using engine oil in the tranny, it never seemed to get answered as the subject of the dipstick took over? Glad to see that I haven't been the only one feeling a bit "stunned" trying to figure the dipstick issue out!!

[Liam Wald]

My manual (3gm30F) states to check oil level without screwing the dipstick in. When the oil is clean it is hard to see on the dipstick but if you lay the dipstick against a piece of paper towel you can see the level easily. I just use the same oil as in the engine crankcase (Rotella-T 15-40). Have owned the engine since new. Now at 1200 hours, no problems.

[skipperr100]

Does anyone know where I can purchase a dipstick for the tranny, I have a yanmar 3gm30f, stock trannny.?

[Mike706]

Dockhead,
I have the same dip stick and tranny that you have. I, too, puzzled over where the oil should appear on the dipstick, and after reading all the replies here and other websites, I concur that 1) Don't screw the plastic top down when checking oil levels, 2) When the oil appears on the tip of the dipstick, stop adding any more oil. The paper towel thing is what I use too.
As for the HD designation and weight of the oil that should be used, I have that same question being submitted this week to a petroleum lab here in Tampa that just tested my tranny oil. When I hear back from them I will post the info. I believe the former owner had used Rotella 15 - 40 for diesel engines in the gearbox as well as the engine.
Also, if you ever want to compare the minerals and viscosity reading at 100'C found in a sample from your gearbox to my recent results let me know. The former owner of this boat bought the Yanmar engine and Kanzaki gearbox in 1998. He put over 6,000 hours on the engine, and I assume that many hours are on the gearbox. The sample I just had analyzed had been after 164 hours of operation.

[GordMay]

Greetings and welcome aboard the CF, Mike.

[sailu2]

Did anybody find out for sure if the amount of transmission oil wa 1.3 litres or 450ml as I am having the same problem. Currently in the Canary Islands and having asked two local Yanmar dealers and got two different answers to this query. The model is the same as Dockhead
I sucked out 400 ml of oil but not totally drained it by the plug and put in 1.1 litres and the level is about an inch from the top of the dipstick, it just doesn't seem right. The label on the gearbox states 1.3litres capacity. I have not yet fired up the engine.
Any help would be great

[gamayun]

I don't know about the capacity, but it sounds like you've overfilled the transmission. Was this the first time you'd changed it? The PO might have had it over filled. Is it the Kanzaki transmission? The level needed is close to the bottom of the stick. Very, very close (maybe 1/4" up but I'm away from my boat so can't measure it), and it's very hard to see with clear oil. So try turning the dip stick at an angle to catch the light and that may help highlight a glimmer of the "slick" part. Also, just push stick in and don't thighten the threads when checking level.

[pcmm]

Originally Posted by sailu2

Did anybody find out for sure if the amount of transmission oil wa 1.3 litres or 450ml as I am having the same problem. Currently in the Canary Islands and having asked two local Yanmar dealers and got two different answers to this query. The model is the same as Dockhead
I sucked out 400 ml of oil but not totally drained it by the plug and put in 1.1 litres and the level is about an inch from the top of the dipstick, it just doesn't seem right. The label on the gearbox states 1.3litres capacity. I have not yet fired up the engine.
Any help would be great

According to the service manual. The oil capacity for the KM4A transmission is 0.2l (or 1.3cu in) the 1.3 is obviously wrong! as 200ml (0.2l) is 13cu.in! just fill it with quality straight 20 or 30 SAE oil and add it bit by bit until it touches the scribed line on the dip stick. Check the oil but unscrewing the dipstick, cleaning it off and reinserting it without screwing it in. check the level that way. all of this information is from the service manual on page 1-5 (page 11 approx of the PDF)

[sailu2]

Many thanks for responses. Yes it is the first time I have changed the gear oil, I think it was changed about four years ago. If it was over filled it does not seem to have caused any damaged. I will now extract the new oil and refill to the level on the dipstick which is about 1/4inch from the bottom. Seems crazy to have wrong info label that could serious damage gearbox

[a64pilot]

You may want to check interval between changes too.
Mine uses ATF, but it’s supposed to be changed at every engine oil change, may be excessive but I do it as it’s real easy to do.
I don’t know what your interval is, but maybe four years is a long time.

[Dockhead]

Originally Posted by nicholson31

Dockhead; yes this thread is old but did you ever get the answer to your original question of using engine oil in the tranny, it never seemed to get answered as the subject of the dipstick took over? Glad to see that I haven't been the only one feeling a bit "stunned" trying to figure the dipstick issue out!!

There is a really, really easy solution to the "what kind of oil to use" question -- Yanmar sells their own brand of transmission oil!

[Sailing Drummer]

A tip I learned about "seeing" the oil level - touch the dipstick to the back of your hand, or a rag, and see how much there is. On my trans it's about 1/4". That's very difficult for me to see on the dipstick but very easy to see on the back of my hand or on a ship rag.
Larry