Cirrect oil for Hurth gearbox

[Ric]

Hello,

My boat has a Volvo MD2020 engine with Hurth MS-10LA gearbox. I need to change the gearbox oil. What oil do I use? The documentation rather unhelpfully says "CD SAE15W/40" but am not sure what CD refers to. I went to the completely useless local volvo marine dealer and after a lot of faffing about not knowing what they were doing they sold me some Elf automatic gearbox oil for cars. Is this the right stuff?

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[petery]

I was also recommended to use good quality automatic transmission fluid (ATF) in my Hurth gearbox.

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[steve28]

Automatic Transmission Fluid, "AFT Type A oil only" according to specification DEXRON II (General Motors) and M2 C33 G (Ford).

I use the atf A spec of oil


steve

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[timevans2000]

Mine also uses ATF. However, they are not interchangble! You box is either designed for ATF or engine oil. The name plate on my box specifies ATF

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[MedMan]

Re: Correct oil for Hurth gearbox

I have a Mercedes engine with a Hurth gearbox and the gearbox uses ATF fluid. However, if your documentation says use Diesel Engine Oil (That is what CD SAE15W/40 means) I would thought that was what you should use. Engine oil is much thicker than ATF fluid which is very thin and runny. Your gearbox and seals will have been designed for one or the other and you must use the correct one. Unscrew the dipstick on the gearbox (all you see is a hex nut on the top, quite often painted red) and have a look. If the fluid on it is thin and red it is ATF. If it is thick and brown or black it is engine oil.

The following notes on Engine Oil Rating may help:

API (American) or ACEA (European) Rating. These ratings cover many aspects of the oil's chemistry and can be thought of as 'packages of additives'. The API ratings are the most commonly used and are pretty well always quoted on the can.

API ratings for diesel engines all start with a 'C'. This stands for Compression. You must, must, must always use a 'C' rated oil for a diesel engine as they contain detergents and other chemicals to deal with the specific combustion products of diesel fuel. The next letter denotes the level of sophistication of the remaining package of additives. Each time there is a significant advance in technology a new letter is allocated. Early letters have now disappeared altogether. Thus:

CD is about the oldest rating still found on sale. The handbooks of many older engines recommend CD rated oil simply because it was the best available when the engine was designed.

CF is quite common and is often called High Performance Diesel Oil or something similar.

CF-4 is often called Super High Performance Diesel and is the minimum standard I look for for my Mercedes OM636

SAE Rating: This is a measure of the viscosity (how thick/thin the oil is) Some handbooks give a figure for a single grade oil to use in winter, a different single grade oil to use in summer and a multi-grade oil you can use all year round. Most of the diesel engines I have come across seem to use SAE 15W40. That means it behaves like SAE15 when cold (thin) and SAE40 when hot (thick) So how does it manage to behave like a thicker oil when it gets hot when we all know oil gets thinner when it gets hot? Clever bods these oil boffins. Multigrade oil oils contain long chain molecules which change their properties as the oil changes temperature and produce the desired effect.


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[Ric]

Re: Correct oil for Hurth gearbox

Thanks for that comprehensive reply. My engine brochure quite clearly says API CD 15W/40 - which by your description is diesel engine oil.

However, the mystery continues, because when I sucked out the old oil this morning, dark brown (consistent with CD 15W/40) but quite runny (certainly runnier than the oil I normally suck out of the engine sump) which is not so consistent with it being 15W/40!

I'm aware that one can really screw up the oil seals if one sticks in the wrong stuff, so would like to be sure...

Would automatic gearbox oil still be red after 250 hours of use? Or does it go brown?

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[jsl]

Re: Correct oil for Hurth gearbox

I use ATF in my Hurth. It might go brown, but always with a strong reddish tinge. And it really is thin - much nearer to water than anything one would normally call 'oil.'

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[Ric]

Re: Correct oil for Hurth gearbox

The mystery continues. I asked a volvo mechanic - he insisted that I use ATF. So I showed him the engine brochure, that clearly states CD15w/40. He then didn't know. I think I'll have to get a volvo mechanic to do the oil-change, then at least I'll be able to blame them if it blows up.



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[lezgar]

Don,t use ATf

Your gearbox is designed for mineral oil diesel engine, the same that you have to use in the engine.

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[Guest]

Ford Capri 2.8i

Example of oil designations for gearbox's ....

The original 2.8i used Gearoil and suffered damage to box due to lack of a oil point on one of the shafts.
Instead of fitting the extra oil point - incidentally one or two tune-up specialists knew about this one and fitted it as part of their turbo kits etc. - Ford changed to normal multi-grade engine oil for short period - this also did not work.
So what did they do ? They changed to automatic Transmission Fluid ...... yep exactly that in a manual gearbox. BUT the real kicker was that they would not honour any warranty unless you used Ford labeled Gearbox fluid - still only ATF !! with a fancy label and twice the price.

How do I know ? I owned 2.8i's and went through all three versions !!! and also replacement box's.

So back to the Hurth - mine has ATF .... and yours ?


<hr width=100% size=1>Nigel ...
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[Ric]

Thanks you're the first person who has confirmed what the manual says. But this seems against all the other opinions here and elsewhere.

Are there, therefore, different versions of Hurth gearbox designed for ATF and mineral oil?

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[Robin]

Re: Correct oil for Hurth gearbox

Why not call Volvo themselves? We have a Yanmar/Hurth which indeed takes ATF but I would be very nervous if the manual said use engine oil, gearboxes are expensive!

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[willothewisp]

Mine's a Hurth, and definitely uses ATF only. Why not ask them?

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[Ric]

Re: Correct oil for Hurth gearbox

I've asked Volvo. They said ATF, so I showed them their own instruction manual that says use CD15W/40. They sort of gulped and said in that case they weren't sure.

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[Ric]

I'd like to ask Hurth, but can't find a website by googling. Do you know one?

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[Anchorite]

Re: Correct site for Hurth gearbox

Hurth are now ZF Hurth. Site at <A target="_blank" HREF=http://zf-marine.com>http://zf-marine.com</A>

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[Anchorite]

Re: And on second thoughts...

For people who DO know try <A target="_blank" HREF=http://www.lancingmarine.com>http://www.lancingmarine.com</A>: they've been handling Hurth boxes for (at least) 25 years and are very helpful (they actually use the gear...)

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[scottie]

I think that when volvo 1st used the hurth box it was on lower hp engines and engine oil which is what volvo have traditionally used in light gear boxes and sail srivbes was initially reccomended.
However when the started to use this box and saildrive on higher hp engines atf was required so as to standardise atf was reccomended across the whole range of boxes.
But engine oil was ok for lower hp engines and if engine oil was initially usede it should be continued to be used .
but if in doubt check it out


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[ex-Gladys]

Our Vetus has a Technodrive. The engine manual says engine oil, but the gearbox manual says ATF. I trust the people who made it not the people that bolt it to their engine

<hr width=100% size=1>Larry Botheras

Anderson 26 "Amber"

 

[Avocet]

How odd!

I have a Hurth HBW 50 (smallest box) and it likes ATF - at least that's what it says on the plate AND in the manual. I can't for the life of me think why they would want to use engine oil because that's designed to do a different job. Engine oil has to cope with combustion products that get past the piston rings so it needs a detergent in it. This is (as you might imagine) not the best thing to have in an oil but the manufacturers assume that it will get changed regularly - before it has a chance to "self-destruct". Gearbox oils don't have to put up with high temperatures and they don't have to "clean" up combustion by-products so they don't need the detergent. They are, however, expected to cope with extreme pressures (at the gear tooth contact points) and they are expected to stay in the box much longer between changes. How often does your manual specify the gearbox oil should be changed?

I'm not an oil expert - this is just stuff I've gleaned over the years but I can see the sense in it!

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