What makes ATF meet spec?

[kanling]

I did a search, couldn't find a real answer.

There are lots of ATF fluid specs, Mercon, Dexron III, Toyota Type IV, Chrysler whatever, etc...

Some fluids are made to cover one or two specs (like typical Dexron/Mercon fluids), others are "Multi Vehicle ATFs" that claim to be good for several specs.

It gets me to wondering... what exactly ARE these specs? Do they cover additives, viscosities, or what?

Is a "multi vehicle" ATF better because it must meet the most stringent reqs of each spec or is it worse because it has to make trade-offs to make it fit a narrow overlap between specs?

Good question for Molakule.

I ask because I am in the midst of trying to find a Toyota type IV fluid at a better price than dealer. I just don't understand why it is so difficult to find aftermarket fluids for leading mfrs like Toyota and Honda.

 

[kanling]

Mola, Good stuff.

So, with the possible exception of friction modifiers, I read it to be that a "universal/multi-vehicle" fluid is likely to be better than a fluid spec'd for just one or two types of trannies. (Because it must meet the most stringent specs of each category.)

Am I right? It kind of goes against my better judgement, which would say that a universal solution wouldn't be as good as a formulation specific to a transmission type.

 

[MolaKule]

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I read it to be that a "universal/multi-vehicle" fluid is likely to be better than a fluid spec'd for just one or two types of trannies.

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I don't have that opinion. I feel UATF's are a compromise.

 

[MolaKule]

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It gets me to wondering... what exactly ARE these specs? Do they cover additives, viscosities, or what?

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See this thread:

http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=56;t=000003

The specifications are "Perfromance" specifications in which the fluid is required to: resist shear and oxidation for a minimum period, and to provide and retain dynamic friction coefficient for a number of hours or miles. It must also resist corrosion and resist interaction with certain metals. The viscosity 'range' is also specified.

The specification DOES NOT specifiy the type of oil or additives one must use. The formulator works with an additive company to develop a fluid to meet these specs.

 

[The Critic]

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Originally posted by BrewCityR:
I'm trying to find a suitable value-priced ATF for my girlfriends '99 Corolla.

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The 99 Corolla takes a Dexron-III fluid. You should have many choices for this fluid type. When I was at Wallyworld yesterday, they had Supertech Dexron-IIIH/Mercon for $5.36 per gallon.

 

[BrewCityR]

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Originally posted by kanling:

I ask because I am in the midst of trying to find a Toyota type IV fluid at a better price than dealer. I just don't understand why it is so difficult to find aftermarket fluids for leading mfrs like Toyota and Honda.

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Me too.

My Dad only uses Honda ATF in his '98 CR-V and I'm trying to find a suitable value-priced ATF for my girlfriends '99 Corolla.

 

[MolaKule]

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I don't have that opinion. I feel UATF's are a compromise.

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Let me reword that statement for clarity.

I feel CURRENT UATF formulations are a compromise.

The new Infineum additive package and others may change that in the near future.