Schaeffer's All-Trans in GM 4T60?

[Pablo]

Originally Posted By: Whitewolf
1/ For 2005 onwards yes but even for older transmissions there is improved durability, particularly in severe operation.


In some generic Dex III's yes. In some well designed Dex III's such as Schaeffer's, not so much. In fact in HD applications, modified GM's, etc. A well built Dex III is preferred. A "Dex III" can be formulated to exceed the oxidation, corrosion and other life requirements of Dex VI and yet still have the physical attributes of Dex III at the high temp end (and even better Dex VI at low temps!)

 

[Whitewolf]

Pablo,

The response to your comment is that we are not in agreement (there's a shock, but I think it has happened a few times).

Well designed DEXRON-IIIs were good but the performance window was too big. That was the reason for the 'G' to 'H' upgrade. As technology moved on though even that was not good enough, hence the development of DEXRON-VI. Can a 'DEXRON-III' fluid be developed to meet DEXRON-VI requirements? Well first of all no because since the spec is obsolete it is no longer possible to get an approval in order to prove DEXRON-III performance. Secondly if we are talking about additive systems that were available when DEXRON-III was current and prior to the development of DEXRON-VI then none of the additives available at that time were able to meet the far more demanding DEXRON-VI requirements. That's why new additive systems were needed and that's why even to this day there is still only one approved chemistry. Although I'm sure there will be others eventually.

I'm not sure that I understand what you mean by 'the physical attributes' of DEXRON-III. Typically, DEXRON-VI fluids in terms of film thickness are about a 20% improvement over those of the old DEX-III. Viscosity stability is a vast improvement over most of the DEXRON-IIIs apart from one or two that had no VM. As far as low temp performance is concerned, then since there is no restriction on base stocks (apart from what the specification allows) it's not possible to say 'better than DEXRON-VI at low temps' because there is no restriction on any company blending a DEXRON-VI with PAO and ester if they chose to do so (though why they would do that would be a mystery since existing DEXRON-VI fluids have already shown to out-perform that type of formulation in terms of oxidative stability).

 

[virginoil]

Does the same warning apply to ACDelco Dexron III fluids. As ther are Containers on the shelf still waiting to be sold, after that warning was issued.

IMO there needs to be some common sense applied to a trasnsition period, where providing the shelf life a fluid has not expired, it could be OK.

As I use ACDelco Dexron III fluid only in my 4L60E trans. I think I can get away with one more fluid change using Dexron III from the GM Holden Dealer, as it is clearly endorsed by GM Detroit, Michigan on the Label.

 

[Whitewolf]

The transition allowed the disposal of existing stocks. Those containers should still display the license numbers and production batch numbers.

 

[MolaKule]

The oxidative stability of Dex VI is due in part to improved oxidation inhibitor additives. The basestock, while it may be majority Group III, also contains PAO's and esters for improved film strength and oxidation stability.

 

[unDummy]

Fully backward compatible?
Show me the friction curves of DexronIII compared to DexronVI.
Or, is that arguement only valid with 'other' brand fluids??

If your transmission calls for DexronIII, feel free to use any that are available. If you want an upgrade, use any blend like Mercon-V, uni-multi ATFs, any full synthetic, or DexronVI.

Schaeffers, IMO, is an upgrade to DexronIII. There is NO reason not to use it.

 

[The Critic]

Originally Posted By: unDummy
Fully backward compatible?
Show me the friction curves of DexronIII compared to DexronVI.

There's only one approved additive package for Dexron-VI, so all licensed Dexron-VI fluids will perform the same.

Dexron-VI fluids have improved frictional durability compared to Dexron III, which allows the fluid to give more consistent shift performance through the life of the fluid.

 

[Whitewolf]

"Show me the friction curves of DexronIII compared to DexronVI"


Published information. See SAE paper #2006-01-3242.

 

[unDummy]

But not published here; Not everyone cares to buy every SAE paper for reading. And, I can't sneak everything by accounting.

BTW, many SAE papers are available at your local public and college libraries. If anyone wants to read them, call your librarian before making the investment.

If you want to add the info or quote the paper, go ahead. If you simply mention the paper, that really doesn't answer the question or request.

 

[Whitewolf]

I'm just pointing out that the information is available to those that want it and can be bothered to go and look. I was trying to help by telling you where to look.
The paper illustrates the friction difference between DEXRON-III and DEXRON-VI by showing the comparison in midpoint torque when using the SAE No.2 machine and BW 4329 material. What the results show is that the DEXRON-III fluid maintains about 160 Nm for around 100 hours before dropping rapidly and subsequently falling below the 150 Nm fail mark at about 140 hours. The DEXRON-VI fluid holds about 170 Nm up to around 175 hours then goes into a very slow decline although not crossing the 150 Nm fail limit until almost 300 hours.
If the paper is available at the local library then it would be a good idea to read it since it does contain a good deal of information.