ATF Fluids

Status
Not open for further replies.
BTW, The Boron is an agent separate from the dye.

In some cases, the dispersant used in an ATF is an ashless dispersant which has been phosphorylated and/or boronated with a hydrocarbyl succinimide, which give rise to the Boron and Phosphorous counts.

A small amount of ZDDP may also be used as a primary anti-oxidant.
 
From Question of the Day:

The clutch disc material of Automatic Transmissions, and other wet clutch applications, are made of porous friction materials which are bonded to steel core plates.

Friction materials may include cellulose, carbon fiber, Aramids, fiberglass, or a combination of materials (composites).

Today, composites rule.

Note: Sintered metal composites may be found in HDD applications.

This material must exhibit:

1.) Mu(o), low speed dynamic coefficient; affected by friction material ingredients and ATF additives adsorption

2.) Mu(i), initial dynamic coefficient at high speed; affected by hydrodynamic effects/porosity/compression/roughness.
 
Interesting thread, nice to see informative posts on BITOG again. Mola, what exactly makes ATF +4 so special? From my understanding of the ATF world, most ATFs are some form of Dex/Merc with tweaks made to meet various OE demands. However, ATF +4 is a different breed. I've read AllPar's page on the development of the product but I guess I'm missing the "why" of it's speciality.
 
ATF + 4 has a slightly different Mu(v) (static/dynamic COF) curve verses DexronIII/Merc, and a low Brookfield viscosity spec.
 
I assume you are asking about the Mu(v) of the clutch/fluid system?

Mu(v) is the resulting curve of the frictional characteristics of the clutch/fluid system.

Mu is coefficient of friction plotted on the vertical axis, v is speed of rotating components plotted on the horizontal axis.

The slope of the curve tells us how the clutch/fluid system behaves.


Quote:
From Question of the Day:

The clutch disc material of Automatic Transmissions, and other wet clutch applications, are made of porous friction materials which are bonded to steel core plates.

Friction materials may include cellulose, carbon fiber, Aramids, fiberglass, or a combination of materials (composites).

Today, composites rule.

Note: Sintered metal composites may be found in HDD applications.

This material must exhibit:

1.) Mu(o), low speed dynamic coefficient; affected by friction material ingredients and ATF additives adsorption

2.) Mu(i), initial dynamic coefficient at high speed; affected by hydrodynamic effects/porosity/compression/roughness.



ATF and Friction Modification
 
So essentially what we're looking at with +4 is a fluid that is more shear stable, better at dealing with cold temps, and has a higher level of friction modifiers?
 
Originally Posted By: RamFan
So essentially what we're looking at with +4 is a fluid that is more shear stable, better at dealing with cold temps, and has a higher level of friction modifiers?


Not necessarily a higher level of friction modifiers, but a different mix of friction modifiers in order to get Mu(v) correct.
 
Regarding the Use of ATF as a so-called engine cleaner:

In the early days of ATF when it contained an ester called, "Sperm Whale Oil," and a naphthenic base oil, Group I mineral motor oils at the same time had little or no detergency additive.

When added to the poor Group I mineral base oil it did do some cleaning because it 1) was thinner than the old motor oil, 2) the naphthenic base oil and Sperm Whale Oil made a it a mild cleaner.

Today's ATF has only 4.2% of the detergency as do current motor oils and little to no naphthenics. Saying it differently, current Motor Oils average 24 times the detergency of current ATF's.

Naphthenic base oils have poor Viscosity Indices and tend to oxidize quicker than do Group II through IV base oils, which is why Naphthenics are rarely used, except as "solvers," and only in very low amounts.

Naphthenics HAD to be used back then in ATF's in order to bring the Sperm Whale OIL into solution.

Furthermore today's Synthenic ATF's contain less than 5% of any type of ester and average about 1%, depending on the formulation.

Sperm Whale Oil was actually the "Liquid Waxy Ester" derived from the spermaceti organ of the Whale's head.

Liquid Wax Esters today are synthesized (reacted) using bio-acids and selected alcohols.

If you need an effective engine cleaner due to sludge buildup or ring coking, use any of the current products containing a mix of solvents and run up to temp, shut off engine, and then change oil and filter.

LCD Inc, LC20, is a good slow engine cleaner that both softens and "solubilizes" carbon.
 
Last edited:
Thats my way of cleaning the engine....with ester based engine oils... I usually buy the cheapest (usually motocycle) ester based oil and I am adding it just before my OCI as a "top off"
 
Last edited:
And as I can read here...it is also double "win-win" since esters also help to swell/recondition old gaskets...

Feel free to correct me if I am wrong in my asumptions/acts
smile.gif
 
Last edited:
Originally Posted By: Kamele0N
And as I can read here...it is also double "win-win" since esters also help to swell/recondition old gaskets...

Feel free to correct me if I am wrong in my asumptions/acts
smile.gif



Esters only help to condition seals.
 
Sure.

When discussing seals such as in engines, transmissions, and other driveline components, the context is that of using flexible, elastomeric materials to keep fluids contained within the mechanical system that has rotating components exiting the system, such as protruding rotating shafts.

For a gasket, the context is that of using a material (such as the silicone material you showed) or cork, or some other material to keep fluids contained in and around stationary objects, such as the valve cover gasket on an engine or the pan gasket on an automatic transmission.


Both seals and gaskets "prevent" loss of fluids.
 
Last edited:
Most ATF seal swell agents today are composed of esters:

tris (C8-C24 hydrocarbyl) phosphite ester

Bis(2-ethylhexyl) ester phosphoric acid

Dihexyl Phthalate ester

and the azelamides such as:
N,N'-dimethyl-N,N'-dihexylazelamide, N,N'-dimethyl-N,N'-di2-ethylhexylazelamide, N,N'-dimethyl-N,N'-di-2-ethylhexylsebacamide

Originally Posted By: MolaKule
Esters only help to condition seals.


I see an apparent contradiction here from the two statements made by Molakule.

Perhaps the explanation is that the esters used in regular ATF only conditions seals and the different esters, used in HM formulations, swell seals.
 
Conditioning seals refers to the following actions:

Seal swell,
Seal cleaning,
Seal elastomer molecular replacement.

There are SAE and JoSL papers out there that discuss these mechanisms.
 
Status
Not open for further replies.
Back
Top