Marine gearbox oil.

[Oscarpop]

I need to top up the gearbox oil and have just located the oil.

Is there much difference between engine oil and gearbox oil?

The plate on the gearbox says it should be sae20/30hd . The engineer that did the first service on the Yanmar said that you can tell the difference because gearbox oil smells really chemically.

Anyone know why it smells bad?

Cheers

 

[vyv_cox]

Gear oil contains a high level of additives to cope with very small sliding clearances between the teeth. However, it's not much of a guide to selecting the correct oil! Some Yanmars use the same oil for engine and gearbox, others don't . Best to check the manual for yours.

 

[VicS]

I need to top up the gearbox oil and have just located the oil.

Is there much difference between engine oil and gearbox oil?

The plate on the gearbox says it should be sae20/30hd . The engineer that did the first service on the Yanmar said that you can tell the difference because gearbox oil smells really chemically.

Anyone know why it smells bad?

Cheers

The bad smell is due to additives ( sulfur compounds) which give EP gear oils for hypoid gears the anti wear properties Vyv mentions.

Surely you must have noticed the foul smell of EP 80 or 90 oil used car rear axles and some gear boxes?

Oil for outboard engine gear boxes is usually an EP90 oil containing additional emulsifiers and corrosion inhibitors to offset the effects of water ingress but i know of no reason why oil for inboard marine gearboxes should be any different to ordinary automotive oil.

As Vyv points out some gear boxes use the same oil as the engine and some use ATF. In some case the recommended oil is a hydraulic oil. it is important, therefore, to always consult the owners manual and use the specified type of oil be it EP gear oil, engine oil, ATF, or something else.

( Note that the viscosity grading for gear oils if different to that for engine oils due to being measured at a different temperature. EP90 is not much more viscous than and a grade 40 engine oil.)


What gerabox on what engine are we talking about anyway ???

 

[Amulet]

My gearbox specifies automatic transmission fluid, which doesn't look smell or feel at all like engine oil, so I'd try to find and read the instructions.

 

[Oscarpop]

So the gearbox is attached to a Yanmar 3jh5e.

The gearbox is a km35p

The manual says.... "AP service categories CD. or higher"
"SAE. Viscosity 20 or 30"
As for the oil, it is left over from when I had the engine first serviced. Problem is, the oil is not in the original container, so I can get no Info from the bottle . I just differentiate using my nose.

thhe engine and gearbox were serviced three years ago, and the engineer left me some spare gearbox oil.

I have no reason to think at he didn't know exactly what he was doing, so unless you folks tell me otherwise, I will use the same oil.


But please feel free to comment

 

[Spi D]

Since the cost of 0.35 liter of oil is close to nothing I'd replace the lot with a known good product according to specs.

Single grade specified or multigrade covering 20/30 will do fine. Might be hard to find CD as standards now have reached CJ, but it will be right anyway.

Edit: See [U]www.apicj-4.org/2009_engine_oil_guide.pdf[/U]

 

[vyv_cox]

The info in the manual is telling you it is engine oil. When it was written there was a belief that monograde oils, e.g. SAE 30, were better than multigrades. That is not a view that is widely held today. I suggest you buy a multigrade 15w-40 to API CF-4 and use it for engine and gearbox. Oils of this type are widely sold in supermarkets at reasonable cost.

 

[westhinder]

So the gearbox is attached to a Yanmar 3jh5e.

The gearbox is a km35p

The manual says.... "AP service categories CD. or higher"
"SAE. Viscosity 20 or 30"
As for the oil, it is left over from when I had the engine first serviced. Problem is, the oil is not in the original container, so I can get no Info from the bottle . I just differentiate using my nose.

thhe engine and gearbox were serviced three years ago, and the engineer left me some spare gearbox oil.

I have no reason to think at he didn't know exactly what he was doing, so unless you folks tell me otherwise, I will use the same oil.


But please feel free to comment

For what it's worth, the gearbox on my Yanmar 3JH3E uses the same oil as the engine.