Yanmar Gearbox Lube Oil Questions

[Dockhead]

My Yanmar JH3HTE has a Kanzaki KM4A gearbox. I changed the oil in it today, and I have a couple of questions:

1. The manual specifies either 20W or 30W HD oil of API classification "CC or higher". Is there anything wrong with using the same oil as goes in the engine, that is, 15W-40 API CF4? I can't imagine what would be wrong with that, but I thought I would ask.

2. As usual with Yanmar, it is hard to figure out how to check the oil level. The manual shows high and low marks on the dipstick, with the high mark appearing to be somewhere in the middle. The manual says check the oil with the dipstick "fully inserted", although the dipstick screws in.

The problem is that my dipstick only has one mark:



The upper mark on the dipstick in the manual appears to be around the middle of the dipstick, so I filled the gearbox, with about one liter of oil (total capacity 1.3 liters according to the manual), to about the middle of the dipstick, with the dipstick screwed in. Does that sound about right to you all?

Thanks in advance for all advice.

[Horror Hotel]

My brand new yanmar tranny (KM2P-1) also appears to be missing the upper mark. The manual shows a upper and lower mark roughy 1" or 1 1/2" apart. The manual states that it takes .32 qt total. The mounting angle is a few more than the 8* listed in the manual so the engine takes a little more oil to be correct on the dip stick. I assure my trans is the same being on the same rake angle.

[Tim R.]

I recall that the only mark on my dipstick is the upper mark. When I fill the tranny with the correct amount of oil it comes up to that mark. I also have a KM4A.

[Dockhead]

Originally Posted by Tim R.

I recall that the only mark on my dipstick is the upper mark. When I fill the tranny with the correct amount of oil it comes up to that mark. I also have a KM4A.

Does your dipstick look like the one in my photo?

[svseachange]

Just got done changing my transmission fluid. My Yanmar 3HM35F transmission dipstick only has one mark (the upper one).

Are you sure you pumped/drained all of the old stuff out? I measure how much I take out to make sure.

[Horror Hotel]

My lower mark ( the only one) is the low oil level. When filled with the .32 qts it's about 1 1/4" higher and at the place where the manual say a second mark should be. My dipstick looks just like your picture with the lower mark roughly 3/8" from the bottom.

[Dockhead]

Originally Posted by Horror Hotel

My lower mark ( the only one) is the low oil level. When filled with the .32 qts it's about 1 1/4" higher and at the place where the manual say a second mark should be. My dipstick looks just like your picture with the lower mark roughly 3/8" from the bottom.

"filled with the .32 qts"

You mean 1.32, don't you?

Well, I hope I haven't overfilled it. I added one liter of oil after sucking out everything my oil change pump could get, out of total nominal capacity of 1.3 liters according to the data plate. The level is more like 2 or 3 inches above the lower mark, but this is where the arrow is pointing in the photo in the manual. uzzled:

[sailorboy1]

Originally Posted by Dockhead

2. As usual with Yanmar, it is hard to figure out how to check the oil level. The manual shows high and low marks on the dipstick, with the high mark appearing to be somewhere in the middle. The manual says check the oil with the dipstick "fully inserted", although the dipstick screws in.

Mine says that too and I used to screw it in all the way and then try to screw it out before the oil ran down the stick. I even thought of making a wooden dipstick just for doing the level check.

But I read a tech note from Yanmar that says it is OK to check the level by sticking the dipstick in without screwing it down. I can not remember where I read it, but that is what I now do and figure that at worst there a little more oil that needed but not a problem. (haven't blown up my gearbox or anything)

[Jsol]

I had the same confusion with the manual on my new Yanmar, so I called Mack-Boring. I was told that Yanmar uses the same manual for different versions of the Tranny. Some models have the high/low marks and some just the high mark. I ave the same dipstick as in the OPs photo and that is the high mark for my Tranny according to MB (all Kanzakis).
However, the one thing that still bothers me is when I put the correct amount in (.3l in my case), it appears to fill significantly higher than the Mark and I'm pretty sure I am draining almost all of it out. At this point I have been filling to the only fill mark.

[Dockhead]

Originally Posted by sailorboy1

Mine says that too and I used to screw it in all the way and then try to screw it out before the oil ran down the stick. I even thought of making a wooden dipstick just for doing the level check.

But I read a tech note from Yanmar that says it is OK to check the level by sticking the dipstick in without screwing it down. I can not remember where I read it, but that is what I now do and figure that at worst there a little more oil that needed but not a problem. (haven't blown up my gearbox or anything)

Only Yanmar could possibly make it so complicated and ambiguous to bloody check the level of lube oil with a dipstick. Sheez.

Don't we love to hate this or that about our Yanmars.

But today I was reflecting on other things -- the positive qualities of these machines. Today while I was running the engine up to check for oil or seawater (after change of impeller and seawater pump cover with a Speedseal), I was thinking with some wonderment that I don't think I've ever before had any kind of internal combustion engine which didn't leak or weep a single drop of any kind of fluid. It's incredible! Not a single drop of oil, or a single drop of coolant. The polar opposite of the Westerbeke in my previous boat, which spewed oil in all directions, and required diapers.

The other thing I love about this engine is its sound. It makes such a mellow, harmonious sound -- it's actually changed my ideas about four-cylinder engines. It's amazingly smooth and mellow and quiet. It sounds happy at its work. I do think that a harmonious sound does often correspond to mechanical harmony and lack of internal stress in an engine. Hope that's the case here.

[Horror Hotel]

We have different transmissions, but my manual clearly states .32 qt and it's full at that amount. So 1/3 of a quart it is and it's very clear about not overfilling it. It's a tiny unit that's the size of a large pineapple, weighing 27 lbs, it's on a new 3YM30.

[Dockhead]

Originally Posted by Horror Hotel

We have different transmissions, but my manual clearly states .32 qt and it's full at that amount. So 1/3 of a quart it is and it's very clear about not overfilling it. It's a tiny unit that's the size of a large pineapple, weighing 27 lbs, it's on a new 3YM30.

Oh, I see.

[Tim R.]

Originally Posted by Dockhead

Does your dipstick look like the one in my photo?

Yup, just like it.

[Tim R.]

Originally Posted by Dockhead

"filled with the .32 qts"

You mean 1.32, don't you?

Well, I hope I haven't overfilled it. I added one liter of oil after sucking out everything my oil change pump could get, out of total nominal capacity of 1.3 liters according to the data plate. The level is more like 2 or 3 inches above the lower mark, but this is where the arrow is pointing in the photo in the manual. uzzled:

That transmission has a drain plug on the aft stbd side. You should drain the oil that way rather than pumping from the top.

[Horror Hotel]

Pump, then drain the last bits. Less mess.