Originally Posted By: Whitewolf
Originally Posted By: dailydriver
Originally Posted By: Whitewolf
In the case of DEXRON-VI I believe it was never tested and validated.
The reality is that testing and validation requires resource expenditure and if there is no problem and no advantage why do it?
I don't just think it was a "testing and validation" issue, as the Dex 6 IS actually too thin (by specced cSt @ 100*C) for use in, or the protection of a T56 OR TR6060.
AGAIN; Penrite, PLEASE PLEASE make your Pro Gear 70W-75 MTF available over here!!!
DEXRON-VI starts at a lower viscosity but does not shear down as much as DEXRON-III did so the 'too thin' argument is just silly.
It's absolutely not silly.
You overlook the fact that Dex III starts out thicker.
There are numerous examples of ruined manual transmissions from the use of factory filled Dex III that was past it's use by date(That's the issue).
Also transmissions that are used in arduous applications which have not done too well with a fill of Dex III.
Hence the quest for a fluid(any fluid) that does a better job of protecting the internals whilst still balancing proper synchroniser functionality.
In some race applications, there are people who are using thicker fluids.
The too thin argument has merit, and it's entirely dependant upon application.
Dex VI is just fine for Auto's designed to use it.
When Dex VI first emerged it was back spec'd for Dex III applications by GM.
In order to preserve the transmissions over the nominated service interval(filled for life), GM eventually increased the nominated fluid quantity of Dex III by 10%.
GM continues to use a non-Dex III fluid as the factory fill, and happily supplies a non-Dex III fluid as a service fill.
At the time GM omitted to state that it didn't apply to the bigger manual transmission they were using at the time and continue to use.
I believe it was over looked and I think a TSB was issued in this regard.
There were people wanting to put it into their T56 transmissions thinking it was going to be the next "big thing". It didn't work out that way for them at all.
Guess what they are running in the units now?
No vehicle manufacturers spec a non-Dex III fluid for the T56/TR6060 for a number of very very good reasons.
Tremec knows full well, the minimum lubrication requirements of their transmissions and advise accordingly.
I would be inclined to think that they wouldn't waste their resources trying to validate Dex VI knowing full well the outcome.
