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I tried something different this year and went for the cheaper storage rates in exchange for allowing the yard to do some of the haulout work. :eek:

Imagine my surprise when I saw on my bill "1 QT DEXRON ATF".

I deferred my freak out until I confirmed this wkd that indeed there was ATF in the gear (Kanzaki 2.62 attached to my Yanmar 2GM20F). FWIW, the service manual does specify SAE 30 or equivalent motor oil for the gear.

So, I, with restraint, politely inquired with the yard manager today over the phone about the use of ATF in the gear. He replied that they "checked with Yanmar and they indicated Dexron ATF was appropriate".

Should I save myself a call to Mack Boring to confirm? Who can tell me the correct lube for this tranny?

Jason
 

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What transmission do you have? My Yanmar can have 4 different transmissions according to manual. The one specifically installed on my boat takes what manual calls "ATF-A". Since no such beast seems to be available anywhere and noone knows what "ATF-A" stands for, it is filled with regular ATF fluid (there are a few out there, I selected the one for the oldest possible American make :) ). One of the 4 possible transmissions takes oil. So - it could be either.

BTW, mechanic that I had over on my boat once specified a wrong amount of ATF fluid for my transmissions, which (as I checked later) matched another transmission from the list. Good thing I double-checked and filled according to the manual - or else there would be less than 1/4 of the required fluid there. So, these mechanic guys definitely could be wrong - trust your manual but read it carefully too.
 

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My 1980 Yanmar 2QM15 takes the DEXRON ATF. There is a fill line marked on the dipstick that the fluid level has to be filled to with the dipstick unscrewed and just sitting on the access point.
 

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I have 4,400 hrs. on my year 2000 4JH Yanmar with the Kanzakee transmission. For the first 3,500 hrs. I ran it with the ATF Dextron II as filled first by the Yanmar dealer that installed the engine. I damaged my transmission at about 3,500 hrs. due to a faulty control cable setting and the mechanics that rebuilt it filled it with the "proper" 30 weight oil. I've remained using the 30 weight oil, but my anecdotal evidence implies that it functions well with either fluid. Aythya crew
 

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This is an interesting discussion. I don't have a Yanmar. My Volvo tranny drinks the 15W-40 stuff, same as the engine, nice and convenient that way. Never heard of ATF on a boat, but it makes sense in a lot of ways. Many newer gear boxes, transfer cases & such use ATF. It is better for fuel economy, and probably better at resisting emulsification than heavier oils.

I think ATF is chemically similar enough to motor oil where it won't damage the seals, might actually help a little. However I agree that it would be prudent to have them put in the correct oil based on the published tranny specifications.
 

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ATF is also recommended in some mechanical transmissions as it also has defoaming agents in it. I have know certain mecahnical transmission dump their oil through foaming, AFT was used and the problem went away.
 

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I can't believe that I've just read a thread where a consensus seems to be forming that you can substitute SAE 30 motor oil for automatic transmission fluid.

I'm speechless.

There's a lot of bad advice circulating on this site.

By the way -- You all do know that there's a difference between gasoline motor oil and motor oil formulated for diesel engines, right?
 

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I think the answer here is that the person needs to know a specific transmission model (which cannot be established based on engine model, since same engine can be fitted with different transmissions). So, we just don't know.
 

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I think the answer here is that the person needs to know a specific transmission model (which cannot be established based on engine model, since same engine can be fitted with different transmissions). So, we just don't know.
Perhaps you're right. I wanted to terminate what I thought was a developing acceptance of substituting ATF and motor oil before someone ruined their transmission. That's completely unacceptable. Maybe I'm just getting a little fed up with some of the answers I've read here over the last couple of months. Maybe it's the weather...
 

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Hi all. I read this site a lot and love the information. To NOLA, I worked on cars in the 70's -80's and there were some manufacturers (I specifically remember Chrysler) that put ATF in their manual transmissions at the factory and allowed standard 10W30 to be used after the transmission had worn.

Yes - there are some applications that allow ATF or motor oil to be used. I don't know if this applies to marine transmissions, but it could! Check your facts before you berate others.

P.S. Yes, there is a difference in motor oil for gas and diesel engines.
 

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Yes - there are some applications that allow ATF or motor oil to be used. I don't know if this applies to marine transmissions, but it could!
Rumor on the street is that Marvel Mystery Oil is basically just ATF with a couple tweaks here and there in the additive package. Think that is true? I haven't tried that in any manual transmission yet, and don't think I will, but I can attest it sure works magic in gas engines. Frees up stick lifters, stops leaking seals. It mixes quite well with oil. My truck was running really low oil pressure (stuck relief valve I think) after a quart of MMO and a couple trips around the block the oil pressure was back to normal and no more tap-tap-tap in the morning. A4 owners also swear by the stuff. Little off topic but just thought I would pop something into this thread before it turns to a poo tossing contest :eek:
 
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