Comma EP80W90 GL5 Differential oil recommended

[martini]

I am about to change my diff oil and saw that the MMOC has had some posts regarding a possible problem with the additive in the GL5 type. So, me being the worrying type, I contacted the Comma enquiry address today. This is how it went...

From: martini
Sent: 25 June 2013 14:59
To: Comma Oil Enquiries
Subject: rear axle differential oil

Hi, I have a 1969 Morris minor and I have been advised that the GL5 additive in the oil can attack yellow metal such as phosphor bronze which is in my rear diff. I have been told to use that type only if there is a notice on the bottle which says that it is 'yellow metal friendly'. Can you clarify this for me and let me know if I can safely use your product in my cars diff?

Thanks for your help,


Their much appreciated timely reply...


Comma Oil & Chemicals Limited
Dering Way, Gravesend, Kent DA12 2QX

Hi Martin,
The manufacturer’s specification for this car calls for a GL5 product with either an SAE 80 or 90 viscosity. In this case our EP80W90 GL5 would be recommended. However, this product is not primarily formulated for yellow metal friendly claims, but it has been made and sold for many years and we have never had a problem or claim with any of our recommendations using this product.

Having said that we are aware that for some very old cars there may have been an issue but there have certainly been none with our products. If your still concerned about this you should seek out a product that is labelled as yellow metal friendly however we’d be interested to know who makes this as we are not aware of anyone who makes this claim.

Regards

Manjit Sanghera
Customer Services Advisor
Telephone 00 44 (0)1474 546208

Fax 00 44 (0)1474 333000

Email M.Sanghera@commaoil.com

Website http://www.commaoil.com

I am now feel happy about using this product... but does anybody on the forum know who makes the oil with 'Yellow Metal Friendly' stated on the bottle?

[MarkyB]

we have never had a problem or claim with any of our recommendations using this product.

This made you happy?
I'm afraid they all tend to say this kind of thing

[bmcecosse]

Err yes - I was thinking exactly the same ! My understanding is to avoid anything that says 'hypoid' on the label....is that correct?

[philthehill]

Why should you avoid Hypoid oil when Morris 1000s are fitted with Hypoid (where the pinion axis does not intersect with the axis of the crown wheel) rear axle differentials?
In the BMC wksp manual issue 7 General Data page 7 it says use Hypoid oil only! See also Section PP 2 - B.

[bmcecosse]

I know that Phil! It's just something I believe I read a long time ago..... I use EP90 Castrol - no mention of 'hypoid' or 'safe for yellow metal'.

[philthehill]

BMC
I agree that EP90 (extreme pressure 90) is the correct oil to use in the Morris back axle but in section PP2-B it says under Castrol - Hypoy (not EP90) which may or may not cause confusion to other post readers and that is why I asked the question.
You have to remember that not all post readers have enjoyed an indentured apprenticeship in a Morris/BMC garage as I have and have the depth of knowledge that you have and therefore may need a bit more background. As they say in the advert 'every little helps'

[martini]

we have never had a problem or claim with any of our recommendations using this product.

This made you happy?
I'm afraid they all tend to say this kind of thing

Perhaps I'm being a bit naive in accepting the oil companies word for it. It's unlike me to trust anything Big Business says or does but I really do need to get some oil for my car soon and the GL5 is the only one stocked in my local car accessory shop. The supermarkets and Wilko's don't stock gearbox or axle oils it seems. I suppose I need to do more research. I've seen it mentioned that the GL4 is suitable but I think I'll check it out first somehow.


Martin

[Trickydicky]

Is this not suitable?http://www.halfords.com/webapp/wcs/stor ... yId_255220

[martini]

Is this not suitable?http://www.halfords.com/webapp/wcs/stor ... yId_255220

Who knows, if we can't trust what the manufacturers state? I was happy but now I'm confused.

Perhaps there is an independent oil testing laboratory which has no affiliations with any oil company and who has carried out lab tests on modern oils and their interactions with 'yellow metal' and has released their findings to the general public. I wonder, does any such publication exist and can their report be trusted to be impartial? I've yet to find it.

This article is interesting... http://www.machinerylubrication.com/Rea ... es-effects
It states that 'active sulfur' is the culprit for the damage to yellow metal as shown in this image...[frame][/frame]

[Trickydicky]

I could be wrong but as far as I am aware there is no "yellow metal" gears in the diff of a Morris Minor, I could be wrong. Without stripping one down and from photos I have seen they are all steel hardened gears running in roller bearings so with respect I cant see what the problem is with using Hypoid EP90 oil in the diff?, its what I use.
If it makes you feel any better you could just change it more regularly?

[IslipMinor]

There are bronze thrust washers behind the planet gears in the diff itself - these have been believed/known to be 'eaten' by EP additives.

From a previous posting EP90 GL4 was the recommend type for the rear axle, I think? Lots of comments if you Google GL5 about eating yellow metals and you should use GL4.

The manufacturer’s specification for this car calls for a GL5

This is not true and worries be greatly as neither Comma nor the API rating existed when the Minor was first made, or probably not during its whole production life!

Interestingly Mobil are very clear in saying that any axle with yellow metal should only use GL4 - this is their website statement:

'There are transmission applications that recommend API GL-4 type products where we would not recommend using an API GL-5 fluid because transmissions typically have components made from “yellow” metals. However real axles where GL-4 fluids are recommended do not have “yellow” metal components. As a result, the application of an API GL-5 fluid is acceptable.'

The typo is theirs, not mine (real)!

I would only use a GL4 EP90 oil in the Minor rear axle, or more likely these days an EP80/90, but still to GL4 standard, not GL5.

[martini]

Perhaps I should first have asked the question:

''Does anybody know if the 1969 era differential has any 'yellow metal' internals''?

I could always look in the BMC workshop manual .pdf and refrain from asking questions that I have the ability to check for myself of course...

[martini]

...I would only use a GL4 EP90 oil in the Minor rear axle.

How about this then... Submitted to http://www.macysgarage.com/myweb6/gear_lube.htm by a chemical engineer, working in the petroleum industry:

''...and you’ll learn that GL-4/GL-5 are performance specifications, not manufacturing specifications, and do nothing to limit the amounts of compounds harmful to the soft metals in our Triumph gearboxes.
Whether a particular manufacturer uses active or inactive Sulfur EP agents is really only known by them. API, GL-4 and GL-5 are performance specs, not a formulation specs...''

and the article goes on to say:

''So there you have it. GL-4 and GL-5 designations tell us nothing about the active sulfur content of the oil, which is the ingredient that may damage the yellow metals in our gearboxes. It’s also interesting to note that GL-4 is not as capable of withstanding shock loading as GL-5 oils...''

The plot deepens... a test for checking active sulfer content is by dipping copper strips in the oil at different temperatures and check to see if it gets stained...
perhaps I will just put the GL5 in and if the bits of 'yellow metal' collapse in a few years time I'll put new bits in, providing of course that I haven't fallen off of the perch already...

[bmcecosse]

As above - the thrust washers and perhaps bearing cages (?) are the problem. Well done Richard for doing the research - looks like GL4 is the way to go. My Castrol EP 90 doesn't have a 'GL' rating - but doesn't seem to have done my diff any harm so far!

[GreenGiant57]

I have used Castrol EP90 in 3 Morris Minors (4 differentials), spread over 50 years and 300,000 miles without any problems.

[IslipMinor]

I emailed Castrol and, like Mobil, they also do not recommend using the GL5 spec oil with axles containing yellow metals - this is their reply:

Thank you for your email

Historically the GL-5 products contained sulphur compounds as part of the EP package and at high temperatures could be quite aggressive to yellow metals - causing pitting most likely, rather than dissolving the metal before your eyes! However, modern oils tend to use different chemistry that isn’t as aggressive, although we would still suggest not using a GL-5 product where a GL-4 one was specified.

My suggestion would be to use a product such as Castrol Universal 75W-90, which has a special additive package that mimics low and high EP oils, so can be used quite safely where yellow metals are present. If that isn’t available then I would suggest a GL-4 80W-90 as the next best alternative.

Also answers Comma's point about 'safe with yellow metals' at the same time.

I think the main thing is that the oil has to be suitable for a hypoid crownwheel and pinion, and must not contain high levels of 'active sulphur', so EP90 or EP80/90 GL-4 would seem to be the one to use.

[martini]

I emailed Castrol and, like Mobil, they also do not recommend using the GL5 spec oil with axles containing yellow metals - this is their reply:

Thank you for your email

Historically the GL-5 products contained sulphur compounds as part of the EP package and at high temperatures could be quite aggressive to yellow metals - causing pitting most likely, rather than dissolving the metal before your eyes! However, modern oils tend to use different chemistry that isn’t as aggressive, although we would still suggest not using a GL-5 product where a GL-4 one was specified.

My suggestion would be to use a product such as Castrol Universal 75W-90, which has a special additive package that mimics low and high EP oils, so can be used quite safely where yellow metals are present. If that isn’t available then I would suggest a GL-4 80W-90 as the next best alternative.

Also answers Comma's point about 'safe with yellow metals' at the same time.

I think the main thing is that the oil has to be suitable for a hypoid crownwheel and pinion, and must not contain high levels of 'active sulphur', so EP90 or EP80/90 GL-4 would seem to be the one to use.

I agree, after seeing emails from Castrol and Comma. This is the one I got back from Castrol:

From: INDTECH UK <INDTECH@castrol.com>
To: martin
Cc: Industrial Customer Service (Castrol) <IndustrialCustomerService@castrol.com>
Sent: Wednesday, June 26, 2013 4:56 PM
Subject: RE: Oil additives

Hi Martin,
Castrol Manual EP 80W-90 has no active sulphur.
This type of API GL 4 gear oil requires an EP (Extreme Pressure) package we use a Sulphur Phosphorous additive to achieve the desired performance this is a passive additive system.
Kind Regards
Geoff & Steve
Technical Support Engineers
BP Industrial Lubricants & Services

And this is what I got back from Comma:

Hi Martin,
Sorry for the delayed response I had to get technical to check this, the Comma EP80W90 GL5 does contain sulphur at about 2.3%, although we are not sure what you mean by active or inactive. Sulphur is part of the additives package in this product.
Regards
Manjit Sanghera
Customer Services Advisor
Telephone 00 44 (0)1474 546208
Fax 00 44 (0)1474 333000
Email M.Sanghera@commaoil.com
Website http://www.commaoil.com

So I'm going to go with the Castrol product.
Thanks to all for the help again, it's much appreciated as usual.