AGL-1, AGL-4

[eddievan]

Hi, in order to reduce the amount of different oils onboard I am investigating this matter.

I have recently bought a sailboat with these oil specs, recomended by prevoius owner.

Engine oil: SAE10/40 (4 cyl diesel)
Gearbox: ATF Dexron III
Propeller shaft seal bearing: SAE 75/90W
Bowthruster ? (looks like same as SAE 75/90W)

I know that some gearboxes have normal engine oil, whats the prerequisits for those (straight or angled sprockets?)?

AGL spec oils; my thinking here is that the higer number (ex. AGL-4) the higher gearboxes (bigger that is), that needs to be able to throw the oil upwards to higher located shafts inside the box. Otherwise they have approx the same spec regarding the lubrication functions.

Transmission oils general; Do they have the same "oil base" as "normal" engine oil but just dyed red to sort them out for their specific "other" functions (see above about AGL oils)?

Question; what do you think would happen if I have engine oil at all places?

[Boracay]

Have you checked the manufacturer's recommendation for each of your machines?

These all look quite different. No chance of interchanging them.

[Dockhead]

ATF is quite a bit thinner than engine oil. Don't mess around with it - be scrupulous about exact oils specified by the manufacturer. And don't substitute a different grade of engine oil in your engine, either.

[eddievan]

Hi again, my bowtruster says Gear Oil EP90.

Found another thread on internet saying:
Quot: You should be able to use a SAE 90 oil which is a GL5. I use a Royal Purple synthetic oil in a 80W90 and it is also a GL5. I was just at Advanced Auto Parts and they had the SAE 90 and so did Walmart. I use the 80W90 in all the gear boxes and change it once a season in the snowblower and the mower gear box. End Quot.

This clarifyes a little bit on the way

The viscosity is a way to make the oil seal different gaps, thats why you should never use full syntetic oil in an old engine, it will just leak.

Summarizing so far:
I think I will be able to use AGL-5 in at least my engine gearbox and my bow thruster, or at least AGL-4 depending if there are any yellow metalls involved.

When the manufacturer recomends a specific type of oil the also concider the metallurgic of the parts lubricated, that is actually my biggest concern.

Back to my question, is there anyone out there that uses engine oil in all the gearboxes in its boat?

[sdowney717]

you can use engine oil in a velvet drive, but ATF is better.
I was told ATF for high speed rpm's
Besides thinner here makes for easier turning so less parasitic loss.
I have thought of going to a synthetic ATF in the gear box as I think it turns freer with less loss. I do notice if the gears are cold, and the shaft disconnected, the output flange can be quite stiff to rotate by hand versus when it is hot. Only two reasons to go to a synthetic for me is perhaps less friction, better heat stability so oil wont break down and the gears last longer?

Of course they already are 40 yrs old

[eddievan]

Hi, thanks for your replies.

After some investigation I have come to decision.

I will service the engine with normal engine oil (of course) but I will use the oil spec EP-90 in all other gear boxes.

This is a quick summary.
Engine Gear Box manufacturer Whurt recommends AGL-1
Propeller Shaft Seal Bearing previous owner recommends SAE75/90W
Bow Thruster Gear Box Side Power SP75T recommends EP-90

My thinking is that the EP-90 will not damage the gears om the Engine Gear Box and it will definitly seal and lubricate the Prop Shaft Bearing.

TIme will tell

[evm1024]

Dredging up memory so check the facts.....


Any gearbox that specifies GL-1 should not have GL-5 put in it. As I recall GL-5 has compounds in it that will attack some of the metals (brass?) used in older gearboxes that require GL-1. I think that I recall that it is the sulfur content in GL-5 that becomes sulfuric acid that eats the brass. But don't quote me on that.

So any oil used should state that it can be used in older transmissions that require GL-1.

Regards, Ethan

[eddievan]

Hi Ethan, yea you are right, the GL-5 standard is only for transmissions that have No yellow metalls and its like you say, because of the metallurgic reactions.

What I discoverd since last time I wrote in the this thread is that my gearbox have cones iinstead of lamell couplings within, I dont think EP-90 have enough low viscosity to be runned in it, so I will not go with anything other than the recomended fluid in the gear box.

But the bowthruster and propeller shaft seal bearing will do good with EP-90.

I did come 25% of the way anyway, did go from 4 fluids to 3

[eddievan]

Yesturday I talked to a person at a company htat sells their own oil, Agrol.

He said that a diesel engine used in my way should have an 20W/40 oil, and in the gearbox I should have Dexron III (that is a non API GL standard), the propeller bearing shaft seal and the bow thruster can use an 75W/90 (that corresponds to an API GL-5 standard).

He also said that if I wanted to use an engine oil in the gearbox I should only use a single grade 10W oil, but this oil should not be used in the other applications.

So now it seems as if I cannot come any closer to the optimal situation, 3 types of oil and with an overall better knowledge and understanding

[eddievan]

My mistake the 75W/90 is a GL-4 and the 80W/90 is a GL-5, it is the 75W/90 that I will use in the Shaft Seal Bearing and the Bow Thruster.