Originally Posted By: ledslinger
Originally Posted By: Whitewolf
Originally Posted By: onion
Originally Posted By: Whitewolf
Yes I do happen to know.
Awesome. Now could you give us some detail as to what specific criteria Trasnynd failed to meet? And some data to go along with it?
Thanks.
I think that I have already done that and quoted SAE papers to support my opinion.
Whitewolf- Is the info in the SAE paper about Transynd failing to meet DEXIII H specs consistent with TJ stating it is due to causing shrinkage of a few nearly obsolete seal materials? Since Allison had to change some seal materials to allow DEX VI, it seems Transynd is friendlier to seals than DEX VI. As noted DEX VI doesn't meet DEX III H either, and if tested for that obsolete spec, it would likely fail for the same reason as Transynd.
It appears to me based on the info at hand, your contention that DEX VI is a superior fluid than Transynd, if based on Transynd's failure to meet DEX III H specs, is a faulty conclusion.
Allison went through an expensive process to develop Transynd and the result is a fluid that doubles the change interval in severe conditions such a garbage trucks that may endure 30 or more duty cycles/mile.
A chosen base oil isn't the last word of fluid performance, but when PAO is specified, it indicates a desire to formulate a durable and stable fluid that offers superior performance at both ends of its operating temperature range. DEX VI, at best a group III and possibly a blend, isn't likely to be as durable in extreme conditions as a PAO based fluid such as Transynd.
There seem to be a lot of questions in there, I shall answer what I *think* you are asking.
Regarding the seals. TranSynd failed the seal testing, so the answer is "no" TranSynd is not more seal friendly than a DEXRON(R)-VI fluid.
Regarding TranSynd failing DEXRON(R)-IIIH testing. Yes, it failed on the seals, but also apparently exhibits undesirable friction characteristics over time. For clarification, please look at the end torque shown in the SAE Paper and you'll see what I'm talking about.
Your statement that current DEXRON(R)-VI fluids would NOT pass the now obsolete DEXRON(R)-IIIH testing is true. BUT not because as you state it would "fail the seal testing" but because the new specification has a completely different viscometric profile, meaning, the newer generation fluids wouldn't even get through the bench testing. So although you're correct in saying that DEXRON(R)-VI fluids wouldn't pass the obsolete spec, unfortunately NOT for the reasons you are stating.
Let me give you an example : the old DEXRON(R)-IIIH fluids would start off typically at a KV/100'C of about 7.5-7.8 cSt. By 80,000 miles, they would typically have dropped to about 4.1 or 4.2 cSt. If you take a look at the published data, you'll observe that although a typical DEXRON(R)-VI fluid starts off at only about 6 cSt, after 200,000 miles they are typically still above 5 cSt.
That kind of data just proves, yet again, what I have been stating, that DEXRON(R)-VI fluids exhibit far superior performace than the older, DEXRON(R)-IIIH type fluids, which are of course no longer 'truly' available. Any company can put a DEXRON(R)-IIIH claim on a lable using suitable 'weasel-wording' but without GM policing those obsolete specs, you could be purchasing any old rubbish.
And finally, and you're probably bored by now ... but to answer your question about PAO type fluids being more durable, you have to realise that the use of PAO came into its popularity at a time when most oils were formulated with Group I base stocks. So, yes, at THAT time, it was a massive improvement in durability in terms of oxidative stability primarily.
However, that's around a 20-yr old "concept" and these days, you'll find that similar performance can be achieved by the use of Group III, Group III plus and/or combinations of those base stocks WITH PAO.
I hope that my comments have helped to show you that this really isn't an easy "it passes/it doesn't pass" question, but a far more complicated and far reaching industry objective to achieve continuous improvement which is obvious from published information and data from multiple OEMs.
At the end of the day, if you want to buy TranSynd and use TranSynd then nobody will try to stop you. It's a perfectly decent fluid for its intended application. I just want to make sure people are aware that the latest DEXRON(R)-VI fluids are far, far superior in durability and performance so they can make an informed decision on what to purchase.
Hope that has helped.