Fluids sanity check

[clarksongli]

Like I said....I know that the viscosity's are the same....Both sus and cst. ...flash point is the same....and the chemical composition is the same....I'm not sure what else constitutes a confirmed test....so by that tr test your oil weight scenario would not stand to be true....

[wrinkledpants]

JFP - Do you have any evidence that suggest that whatever fluid Porsche is using - it's completely proprietary to this transmission? Serious question.

Aisin builds the porsche tranny. Aisin also builds most of the Toyota Trannies which have T-IV for fluid. T-IV specs JMS 3309. It's been widely supposed that T-IV is just rebranded Mobil 3309. Mobil 3309 is not synthetic. 3309 is the porsche tranny fluid spec. Oil reports show porsche fluid and T-IV to be very similar in characteristics. Mobil 3309 is certified for the VW spec on the Touareg, which has the same tranny as the cayenne. My local porsche dealer told me that the fluid is just Mobil 3309 . That's not to say they are wrong, or that is the definitive answer, but just about everywhere I look, all signs point to the porsche fluid being Mobil 3309.

[wrinkledpants]

More reading material.

http://www.chemcorp.co.uk/creo_files/upload/related-items/mobil_atf_3309.pdf

[JFP in PA]

Like I said....I know that the viscosity's are the same....Both sus and cst. ...flash point is the same....and the chemical composition is the same....I'm not sure what else constitutes a confirmed test....so by that tr test your oil weight scenario would not stand to be true....

Like your previous statement, this is also open to question. You have values for certain chemicals that are in both fluids, but have no idea in what form(s), and therefor have no real chemical composition. Much like the presumption often made about engine oil's zinc, calcium, and more importantly phosphorus content, it comes from multiple sources, not just ZDDP. So assuming that because two fluids have similar total phosphorus levels means they both have the same level of ZDDP is a major leap of faith, not science. To really know if they are similar, you are going to need a full chemical breakdown and balance, so you know the all the sources and distribution of the phosphorus, calcium, and zinc. Granted, you have made an interesting effort to try and compare two fluids, but you are still going on the basis of the 1/7th of the iceberg you can see, not the total picture, which can take you somewhere other than where you intended.

You also have very limited physical data; flash point only tells you the ignition point of the lowest volatile in the mixture. Much more telling would be coefficient of friction by either SAE or ASTM standards. For decades, Ford and GM used ATF that had very similar basic physical and chemical properties (viscosity, flash point, various chemical concentrations, etc.), but the fluids were totally different in terms of their coefficient of friction, a key factor in how the organic and steel clutch plates wear. Put Ford's high CF fluid in a GM car, the car began to shift very hard, run hot, and the clutches burned up prematurely; put GM's low CF fluid in a Ford, the trans quickly began to show signs of slippage and began to leak. It does not take much.

[JFP in PA]

JFP - Do you have any evidence that suggest that whatever fluid Porsche is using - it's completely proprietary to this transmission? Serious question.

Aisin builds the porsche tranny. Aisin also builds most of the Toyota Trannies which have T-IV for fluid. T-IV specs JMS 3309. It's been widely supposed that T-IV is just rebranded Mobil 3309. Mobil 3309 is not synthetic. 3309 is the porsche tranny fluid spec. Oil reports show porsche fluid and T-IV to be very similar in characteristics. Mobil 3309 is certified for the VW spec on the Touareg, which has the same tranny as the cayenne. My local porsche dealer told me that the fluid is just Mobil 3309 . That's not to say they are wrong, or that is the definitive answer, but just about everywhere I look, all signs point to the porsche fluid being Mobil 3309.

While I have no direct data to indicate that Porsche is using a proprietary ATF composition, it would not come as a surprise if they did. They have done exactly that in other current models, such as the Boxsters. In the Boxster, the five and six speed manual gear boxes have different spec gear oils from different manufacturers, mostly due to the use of different synchronizer alloys (speced by Porsche and the source of the old GL-4 vs. GL-5 argument). And while the factory lube for the five speeds is a pretty odd product, it works very well; and as many have discovered to their dismay, is not easily substituted with an aftermarket product. In fact, when we questioned Mobil directly about a suitable lube for the five speeds, their answer was that Porsche was using such an odd product that they had no suitable substitute, and actually suggested staying with the OEM lube.

While Aisin builds transmissions for several manufacturer's, that does not necessarily mean that they are not all the same internally. Aisin also builds Nissan's non CVT automatics, and you will note that Nissan is not listed in the Mobil UK ATF document you sited. That is because Nissan uses a different spec ATF (believed to be a Pentosin product) because their engineers selected a different friction material for the organic clutch plates in their Aisin boxes.

Porsche does not make their own lubricants, and their ATF could well be made by Mobil or someone similar; but that alone is not a guarantee that what they spec is exactly the same as another over the counter product from the same oil manufacturer .

[clarksongli]

Either way do what you wish. .. I've provided chemical comparisons to the best of my knowledge. ...all far as I can see everyone else just provides their two cents.

Unless someone can prove differently. ...I see no reason not to use type 4.

JFP maybe you can provide a more detailed chemical review of the fluids? Personally I've worked with the folks at the Leipzig factory for aerospace manufacturing techniques and logistics....I can promise you they aren't assembling transmissions there or using proprietary fluids....

[JFP in PA]

Either way do what you wish. .. I've provided chemical comparisons to the best of my knowledge. ...all far as I can see everyone else just provides their two cents.

Unless someone can prove differently. ...I see no reason not to use type 4.

JFP maybe you can provide a more detailed chemical review of the fluids? Personally I've worked with the folks at the Leipzig factory for aerospace manufacturing techniques and logistics....I can promise you they aren't assembling transmissions there or using proprietary fluids....

My space in the Cartesian coordinates of life if to try and fix these cars faster than my customers can break them, which has not been always easy. For anyone other than an oil company with a good research lab at their disposal, it would be prohibitively expensive to develop and maintain a continuous analysis of all the possible products and substitutes on the street. Early in my corporate career, I worked for what was then one of the major oil company's R&D center, and I can attest from experience how difficult in is to stay on top of such a cross reference, particularly when most compounders are altering their formulations fairly regularly, for both economic and technical reasons. This would be impossible for an individual or a shop to attempt to replicate on an ongoing basis.

But what we can do is share what we have learned, often a some expense itself. As I said, you made an interesting shot at comparing the fluids, but I simply wanted to caution you and other readers to not accept limited technical data as gospel evidence that the products were an exact match, and thereby a guarantee nothing could go wrong.

We have had customers that used all sorts of ATF, some with success, others not so much. I think some of the time, the products they have tried are "close enough" that nothing really bad happened. At the end of the day, any individual owner can choose to go any pathway they like, it is their car and their money. As a business owner, I have to pursue a more cautious route; if we do not have direct experience with a given product, we don't put it in customer's cars until we do (often, by testing it in our own vehicles first), and know it is at least as good, if not better than what we were using. My livelihood depends upon that level of certainty.

[bigbuzuki]

Either way do what you wish. .. I've provided chemical comparisons to the best of my knowledge. ...all far as I can see everyone else just provides their two cents.

Unless someone can prove differently. ...I see no reason not to use type 4.....

The only fact I can see is that it is unapproved by Porsche for some reason. Edited May 2, 2014 by bigbuzuki

[wrinkledpants]

It's not "unapproved" by Porsche. Porsche doesn't create a list of oils you can use and ones you can't use. Petrol companies submit samples to porsche, porsche tests the fluid to make sure it meets the spec, and then the oil company is allowed to pay the license fee to list the porsche approval rating on their oil bottle.

You can say "this oil is not currently on porsche's approval list," but it would be incorrect to say "this oil is unapproved by porsche." That would imply that porsche tested it and made a decision to not include it. That's why there are plenty of good oils out there that easily meet the spec, but aren't on the approval list. This is also why you see tranny fluids listing the VW touareg fluid spec, and not the cayenne. It's the same tranny - same fluid.

Typically, you only see giant oil companies on the approval lists, and not the smaller ones. It's not because the oil sucks - but because the ROI on the licensing fees simply isn't there.

Edited May 2, 2014 by wrinkledpants

[bigbuzuki]

If it's only the licensing fee that hasn't been paid, your argument stands.

What we don't know is if that is the case.