MolaKule
Staff member
A Brief History of Automatic Transmission Fluids for Automobiles and Trucks
By MolaKule
In this tech brief we will discuss the history and specifications of automatic transmission fluids.
See the companion Article:
http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=4;t=000147
From the Yahoo reference:
http://ask.yahoo.com/ask/20011022.html
Ford had their Ford-A-Matics, Chrysler later introduced their “PowerFlites” about 1953. For these older “Classics” use Dexron III in lieu of any service manual recommendations.
One thing we know for sure is that American hydraulic technology on aircraft spawned hydraulic power in cars. Hydraulic power had been used to remotely control aircraft systems long before it found its way into automobiles.
As Lubrizol says on their website:
GM needed a specification to give to the lubrication industry and the Type A fluid was borne in 1947. Nothing is known about this additive package.
In 1957, ten years later, GM developed the Type A Suffix A fluid specification and we know this fluid contained 16,250 ppm phosphorus, 37,500 ppm sulfur, 18,500 ppm of zinc, 130,000 ppm of Barium. This additive package was 6.2% by volume of the total fluid.
In 1959 Ford issued the M2C33-A/B specification. Nothing is known about that additive package.
In 1961, Ford issued the M2C33-C/D specification. Nothing much is know (at this time) about its additive package.
In 1967 and 1972, GM issued the Dexron specification which contained 3,500 ppm of phosphorus, 3,200 ppm of zinc, 7,500 ppm of nitrogen, 3,200 ppm of sulfur, and 4,500 ppm of Calcium. This additive package was 10.5% of the total fluid volume. The 1972 formulation specified better oxidation and Friction Modification.
In 1967, Ford introduced the M2C33- F “Type – F’” fluid which contained 12,000 ppm of phosphorus, 4,200 ppm of zinc, 4,000 ppm of Nitrogen, and 800 ppm of Barium.
This additive package was 9% of the total fluid volume.
In 1972, Ford introduced the M2C33- G fluid to the European market with slightly better oxidation specs and enhanced Friction Modification.
In 1973 GM specified another Dexron fluid called Dexron II with enhanced friction modification.
In 1974, ford introduced the M2C138-CJ specification and in 1981 the M2C166-H specification. In 1987 they introduced the first Mercon specification.
Mercon V is now specified for use for all AODE and 4R70W transmissions
GM’s Dexron III and III(G) fluids were current fills prior to 2004.
The specifications for a good Dexron III fluid generally show a 7.0 to 7.75 cSt Kinematic Viscosity (at 100 C) and a 40 C viscosity of 35 cSt. Flash points are about 367 F, pour points are -60 F, and sulfur is 2200 ppm with phosphorus being 620 ppm. The SUS viscosities are 17,500 cP at -40 F and 1,350 SUS for -10 F.
Usually you will see this statement for Dexron III/Mercon Fluids:
“The Dexron III/Mercon automotive transmission fluid (ATF) is generally recommended as a replacement fluid for automatic transmissions meeting original equipment manufacturers (O.E.M.) performance requirements for current General Motors, Ford, other domestic and imported passenger cars, vans and light trucks where DEXRON II, DEXRON II-E, DEXRON III, AND Ford/MERCON fluids are specified. The product can also be used as make-up and full fill fluid in Chrysler transmissions; however, it should be noted that Chrysler MS-7176 type fluid should be used when specified to satisfy warranty requirements.
This fluid is recommended for Detroit Diesel Allison C-3, C-4 applications. It also meets the requirements of Caterpillar TO-2. It is further recommended as a service fill fluid for Ford late model C-4 and C-6 transmissions.
The power transmission fluid is suitable for power steering units where the manufacturer recommends a Dexron or Mercon fluid for its systems. Other manufacturer suggested applications include mobile hydraulic and industrial systems, and rotary air compressors under certain service conditions. ” This statement indicates or infers that Dexron III/Mercon is the most universal Automatic Transmission Fluid available and has wide applicability.
GM has released this year (2004) Dexron III(H) fluid specifications for new factory fill’s in their 5 and 6-speed automatics.
Chrysler and others released special specification fluids such as their ATF+ series to avoid shortcomings in fluid and transmission designs.
Better oxidation stabilization, enhanced friction durability, and wear protection was improved with every new fluid introduction and higher specification level.
The ATF has approximately 12-18 different additives in the base fluid, which is generally a paraffinic mineral oil. Later base fluid developments introduced Polyalpha olefins (PAO’s), di-esters, POE esters, alkylated naphthalenes, and alkylated benzenes for better oxidation and thermal resistance.
Of those additives, Ant-Wear (AW) and Friction-Modifcation additives are the most important. Most frictional materials in automatic transmissions are steel making contact with a steel-backed plate containing a surface made of fiber such as cellulose. The cellulose frictional material is bound by resins and may contain other materials such as carbon, asbestos fibers, or ceramics. The frictional materials in future automatic transmissions will contain mostly carbon fiber composites and ceramics.
Each manufacturer uses different clutch materials so the dynamic friction of each transmission is slightly different, hence the requirement for fluids of different dynamic frictional characteristics.
For heavy duty truck transmissions, sintered bronze and semi-metallic friction surfaces are the norm (such as used in Allison Transmissions).
Friction Modification:
When we use the term, “Friction-Modification” with a hyphen “-“ we infer a special friction additive that affects the “Dynamic” friction coefficients under spinning wet-type clutch plates and drums.
Dynamic friction is defined as the “changing of the coefficient of friction as the sliding speed between two frictional surfaces change.”
The friction coefficient of Dexron III/Mercon fluid increases as the sliding speed increases. The friction coefficient of Ford Type F fluid decreases as the sliding speed increases.
Stating the above sentence another way, Ford Type F fluid has a Low Cf at high speeds, and a high Cf at low speeds. Conversely, Dexron Type fluids have a High Cf at high speeds and a Low Cf at low speeds.
Highly specialized Friction-Modification additives determine the dynamic frictional characteristics of ATF’s. The F-M’s must be stable over long periods of usage; i.e., they must not change their dynamic frictional characteristics for at least 30,000 miles. These F-M additives will not show up in VOA's or UOA's.
Also see:
http://www.baumannengineering.com/alphabet.htm
http://www.edmunds.com/ownership/techcenter/articles/43836/article.html
By MolaKule
In this tech brief we will discuss the history and specifications of automatic transmission fluids.
See the companion Article:
http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=4;t=000147
From the Yahoo reference:
http://ask.yahoo.com/ask/20011022.html
Later GM produced the DynaFlow for their heavier and higher priced vehicles such as Buick, Pontiac, and Oldsmobile lines. For Chevy’s and economy models, the PowerGlide 2-speed was developed. Then along came the TurboHydramatic series, the 700-R4’s, and the electronic versions such as the 4L60E and later variations.quote:
“As we learned, automatic transmission was based on technology first developed in the early 1900s by German manufacturers of marine engines. However, it was not adapted for automobiles for several decades. In 1938, General Motors developed the first line of cars to sport automatic transmission -- Oldsmobiles that offered "Hydra-Matic drive."
Cars with AT's were first introduced to the public in 1940. In 1941, Chrysler followed suit and introduced three different cars that offered their version of automatic drive, "Vacamatic" (later called "Fluid Drive"). Automatic transmission was a fairly common option on most American cars by 1948.”
Ford had their Ford-A-Matics, Chrysler later introduced their “PowerFlites” about 1953. For these older “Classics” use Dexron III in lieu of any service manual recommendations.
One thing we know for sure is that American hydraulic technology on aircraft spawned hydraulic power in cars. Hydraulic power had been used to remotely control aircraft systems long before it found its way into automobiles.
As Lubrizol says on their website:
We don’t know much about the early fluids used in these transmissions except they contained additives similar to engine oils and used the better base oils.quote:
“ATF is the most complex of all lubricating fluids. Not only does it have to reduce friction to prevent wear like all lubricants, but it also has to allow a certain level of friction so clutch materials can engage. Since most OEMs use proprietary frictional materials, virtually every ATF is OEM-specific. In some cases, they're transmission-specific. In addition, ATFs must be compatible with all transmission components, operate at both low and high temperature extremes, and maintain constant performance for extended periods.”
GM needed a specification to give to the lubrication industry and the Type A fluid was borne in 1947. Nothing is known about this additive package.
In 1957, ten years later, GM developed the Type A Suffix A fluid specification and we know this fluid contained 16,250 ppm phosphorus, 37,500 ppm sulfur, 18,500 ppm of zinc, 130,000 ppm of Barium. This additive package was 6.2% by volume of the total fluid.
In 1959 Ford issued the M2C33-A/B specification. Nothing is known about that additive package.
In 1961, Ford issued the M2C33-C/D specification. Nothing much is know (at this time) about its additive package.
In 1967 and 1972, GM issued the Dexron specification which contained 3,500 ppm of phosphorus, 3,200 ppm of zinc, 7,500 ppm of nitrogen, 3,200 ppm of sulfur, and 4,500 ppm of Calcium. This additive package was 10.5% of the total fluid volume. The 1972 formulation specified better oxidation and Friction Modification.
In 1967, Ford introduced the M2C33- F “Type – F’” fluid which contained 12,000 ppm of phosphorus, 4,200 ppm of zinc, 4,000 ppm of Nitrogen, and 800 ppm of Barium.
This additive package was 9% of the total fluid volume.
In 1972, Ford introduced the M2C33- G fluid to the European market with slightly better oxidation specs and enhanced Friction Modification.
In 1973 GM specified another Dexron fluid called Dexron II with enhanced friction modification.
In 1974, ford introduced the M2C138-CJ specification and in 1981 the M2C166-H specification. In 1987 they introduced the first Mercon specification.
Mercon V is now specified for use for all AODE and 4R70W transmissions
GM’s Dexron III and III(G) fluids were current fills prior to 2004.
The specifications for a good Dexron III fluid generally show a 7.0 to 7.75 cSt Kinematic Viscosity (at 100 C) and a 40 C viscosity of 35 cSt. Flash points are about 367 F, pour points are -60 F, and sulfur is 2200 ppm with phosphorus being 620 ppm. The SUS viscosities are 17,500 cP at -40 F and 1,350 SUS for -10 F.
Usually you will see this statement for Dexron III/Mercon Fluids:
“The Dexron III/Mercon automotive transmission fluid (ATF) is generally recommended as a replacement fluid for automatic transmissions meeting original equipment manufacturers (O.E.M.) performance requirements for current General Motors, Ford, other domestic and imported passenger cars, vans and light trucks where DEXRON II, DEXRON II-E, DEXRON III, AND Ford/MERCON fluids are specified. The product can also be used as make-up and full fill fluid in Chrysler transmissions; however, it should be noted that Chrysler MS-7176 type fluid should be used when specified to satisfy warranty requirements.
This fluid is recommended for Detroit Diesel Allison C-3, C-4 applications. It also meets the requirements of Caterpillar TO-2. It is further recommended as a service fill fluid for Ford late model C-4 and C-6 transmissions.
The power transmission fluid is suitable for power steering units where the manufacturer recommends a Dexron or Mercon fluid for its systems. Other manufacturer suggested applications include mobile hydraulic and industrial systems, and rotary air compressors under certain service conditions. ” This statement indicates or infers that Dexron III/Mercon is the most universal Automatic Transmission Fluid available and has wide applicability.
GM has released this year (2004) Dexron III(H) fluid specifications for new factory fill’s in their 5 and 6-speed automatics.
Chrysler and others released special specification fluids such as their ATF+ series to avoid shortcomings in fluid and transmission designs.
Better oxidation stabilization, enhanced friction durability, and wear protection was improved with every new fluid introduction and higher specification level.
The ATF has approximately 12-18 different additives in the base fluid, which is generally a paraffinic mineral oil. Later base fluid developments introduced Polyalpha olefins (PAO’s), di-esters, POE esters, alkylated naphthalenes, and alkylated benzenes for better oxidation and thermal resistance.
Of those additives, Ant-Wear (AW) and Friction-Modifcation additives are the most important. Most frictional materials in automatic transmissions are steel making contact with a steel-backed plate containing a surface made of fiber such as cellulose. The cellulose frictional material is bound by resins and may contain other materials such as carbon, asbestos fibers, or ceramics. The frictional materials in future automatic transmissions will contain mostly carbon fiber composites and ceramics.
Each manufacturer uses different clutch materials so the dynamic friction of each transmission is slightly different, hence the requirement for fluids of different dynamic frictional characteristics.
For heavy duty truck transmissions, sintered bronze and semi-metallic friction surfaces are the norm (such as used in Allison Transmissions).
Friction Modification:
When we use the term, “Friction-Modification” with a hyphen “-“ we infer a special friction additive that affects the “Dynamic” friction coefficients under spinning wet-type clutch plates and drums.
Dynamic friction is defined as the “changing of the coefficient of friction as the sliding speed between two frictional surfaces change.”
The friction coefficient of Dexron III/Mercon fluid increases as the sliding speed increases. The friction coefficient of Ford Type F fluid decreases as the sliding speed increases.
Stating the above sentence another way, Ford Type F fluid has a Low Cf at high speeds, and a high Cf at low speeds. Conversely, Dexron Type fluids have a High Cf at high speeds and a Low Cf at low speeds.
Highly specialized Friction-Modification additives determine the dynamic frictional characteristics of ATF’s. The F-M’s must be stable over long periods of usage; i.e., they must not change their dynamic frictional characteristics for at least 30,000 miles. These F-M additives will not show up in VOA's or UOA's.
Also see:
http://www.baumannengineering.com/alphabet.htm
http://www.edmunds.com/ownership/techcenter/articles/43836/article.html