ATF+4 rant on allpar

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Some good stuff in the article, inc knocks on Lucas and LubeGuard. Frazier wrote: For the full story behind the development of ATF+4, please see SAE paper #982674. It is simply packed with interesting data about the development of ATF+4®. Here are a few tidbits: The initial development was done using Shell's XHVI base oil. Only much later were other Group III base oils approved. (Currently, SK in Korea and PetroCanada are the only additional approved base oil suppliers.) The use of Group III base oils is probably the leading cause for ATF+4 being a more expensive fluid than ATF+3 (which according to the paper uses a Group II base oil). Lubrizol developed a new shear-stable viscosity index (VI) improver specifically for ATF+4. The initial tests of this VI improver in the MS9602 test fluids were so remarkable that Chrysler modified the then-current ATF+2 spec (MS7176D) to include it. Thus ATF+3 (MS7176E) fluid was born; it remained the factory fill until ATF+4. [Lubrizol is still used in ATF+4 and is required in fluids licensed for compatibility.] In testing done during development of ATF+4, Chrysler noted the following viscosity loss from shearing for the following ATFs (20 hour KRL Shear Test): Dexron III - 40% loss Mercon V - 19% loss Type 7176D - 32% loss Type 7176E - 14% loss Type 9602 - 10% loss You can see what a significant impact the new viscosity improver had on ATF+3 when you compare the 7176D and 7176E numbers. From the standpoint of viscosity loss alone you can see why Dexron III should not be used in transmissions that require ATF+3 or ATF+4. In terms of other basic performance parameters, ATF+3 (7176E) comes the closest to ATF+4, with Ford’s Mercon V a close second. [Which doesn’t mean that Mercon is acceptable.] The goal in developing ATF+4 was to create a fluid that would match the performance characteristics of the current fluid (Type 7176D), but would retain those characteristics for at least 100,000 miles. The paper specifically notes that the anti-shudder properties of ATF+3 are usually degraded enough by 30,000 miles to cause noticeable shudder. Contrary to popular myth, one of the stated goals of Type 9602/ATF+4 fluids was that it would have the same frictional characteristics as ATF+3. The paper explicitly states that this was because new clutch materials would not be introduced for this fluid and it had to be backwards compatible with ATF+3. Graphs in the paper show that the friction coefficient of fresh ATF+3 and ATF+4 is essentially identical, but as the fluid ages ATF+4 retains the “as new” coefficient while ATF+3 degrades. The paper noted that one alternative was to use synthetic Group IV base stock, which are even more expensive than the ATF+4 solution, which provided Group IV style performance from Group III stock. ATF+4 meets strict low-temperature, oxidation, and volatility performance requirements and relatively low cost — believe it or not. Manufacturers can make ATF+4 fluids, but to use the trademarked ATF+4 name in their compatibility list, they must have their fluids tested and licensed by Chrysler engineers, and must use Lubrizol in their formulations. Licensed fluids are periodically sampled from stores to assure quality. ATF+3 ATF+3 is a friction-modified, high-quality transmission fluid similar to the current fluid in most respects; but it wears out more quickly and has less desirable cold viscosity (to simplify: is too thick when cold). ATF+3 can be approximated by Dexron plus an additive but this does not save much money and is not as desirable as using the correct fluid to begin with. Dexron itself is the General Motors-specified fluid from far back in automotive history. While it was once the standard for all American autos, that time has long passed, with Ford settling on Mercon and Chrysler on ATF+3 (and now ATF+4); other manufacturers also require their own fluids. Engine oil has been used as an automatic transmission fluid, again in the antiquity of automatic transmissions; it is still used in manual transmissions, but generally a single-grade oil is used. The Center for Quality Assurance, which Chrysler uses to run its ATF+4 licensing program, wrote: “The previous MOPAR ATF+3® formulation was discontinued in 2005 and ATF+4® is recommended for all transmissions filled with ATF+3®.” Several companies now sell "universal" fluids. If they state that they are compatible with ATF+4®, they may work well, especially for those unsure of which fluid to use. The Center for Quality Assurance warned us to check the label for Chrysler’s license number, and to make sure the fluid is on their list of ATF+4® licensed and tested fluids. Usage You can use ATF+3 with all older Chrysler transmissions (except some Jeeps as noted below). Chrysler is not the only company to require a unique transmission fluid. Dexron has long since passed its prime, and modern transmissions require modern fluids, which more refined properties. Toyota, Ford, Nissan, and other major automakers also require unique fluids. Additives David Castater noted: “I used Lucas transmission additive on the recommendation of my local Kragen counterperson... What a mistake!!!! We started seeing shudder at 55+ mph. The dealership told us it was the torque converter dropping out of lockup and the tranny would fail and should be replaced ($3,000). This was a dealer purchased rebuilt transmission less than 4 years old! My local AAMCO manager changed the oil and filter, added a"friction modifier", and reprogrammed the computer. No problems since!!” John C. Lai wrote that LubeGuard, used with Dexron by AAMCO, is not a good substitute for ATF+3, either: "...although Lubeguard claims on their website that their product will convert Dexron to become an ATF +3 (7176E) equivalent, they actually have no test data to back that up. In fact, their head engineer told me that the tests they did were conducted in the early 1990s with the first version of 7176, several years before ATF+3 was developed. So, they have no basis for their claims of ATF +3 equivalency. Spend the extra money for an ATF+4® compatible fluid. \ http://www.allpar.com/mopar/transmissions/fluids.html
 
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Don't see how this is a rant but is good info. The newer Chrysler electronic transmissions sure don't like it if the wrong fluid is used. ATF+4 stinks though...
 
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I wouldn't use the word "currently" with a decade old paper. Group IV oils have good interchangeability with like spec's without having to reformulate for every brand of PAO/PIO base. There is no interchangeability between the brands of Group-III oils since the performance/quality varies greatly, hence selected suppliers for basestocks and other specific ATF brands/types. Some of the info at allpar is good. Some of it is knucklehead garbage. It takes someone with sense to read through their info.
 
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 Originally Posted By: unDummy
I wouldn't use the word "currently" with a decade old paper.
Everything in that SAE paper still stands. Chrysler has not changed the formulation of ATF+4 since it was introduced.
 
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Interesting. I support the view that so called 'universal' fluids might work after a fashion but not up to the standard of a genuine approved fluid. I also am of the opinion (and I have seen evidence to support my opinion) that the so called 'converter' products are generally useless 'snake oil'. Having said that here are some results that you might find interesting. What we're talking about is viscosity loss at the end of a 40 hr KRL:- DEXRON(R)-VI, 6.3% ATF +4, 20.2% MERCON-V, 26.3% If you want to find more detailed information comparing these and other fluids in various tests, try obtaining a copy of SAE paper # 2007-01-3987.
 
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 Quote:
DEXRON(R)-VI, 6.3% ATF +4, 20.2% MERCON-V, 26.3%
Interesting, but Dex VI already starts ~1.5cSt lower than the others, so they have more room to drop. Dex VI is also a ten year newer spec.
 
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I don't like this part.
 Quote:
Dexron has long since passed its prime
As we all know, Dexron has been changed from Dexron-II to Dexron-IIE to the Dexron-III generation ending in the (H) version, to the newest Dexron-VI. Was there ever a Dexron-I? I know that Dexron-IV was a spec that was never produced, and that GM didn't use the Dexron-V name due to the certainty of consumer confusion with MerconV.
 
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The DEXRON(R) brand was introduced in 1967 so that was the first DEXRON(R). DEXRON(R)-II came in 1973 followed by DEXRON(R)-IIE in 1990. DEXRON(R)-III appeared in 1994 and went through several updates until the introduction of DEXRON(R)-VI in 2005. DEXRON(R)-IV was never brought to market and the designation V was skipped in order to avoid confusion with MERCON(R).
 
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 Quote:
I also am of the opinion (and I have seen evidence to support my opinion) that the so called 'converter' products are generally useless 'snake oil'.
While I don't promote the use of additives to "convert" fluids, auto trans rebuilders have done it for decades. In something like warmed over TF904 transmissions, which used Dexron® over its evolutions, the only symptom (and apparent liability in either operation or durability/reliability) was converter clutch shudder. This causes one to ask why GM and MOPAR ..that both used DEXRON, diverged into unique products. Many rebuilders used TYPE F for all remans at one time. Firmer shifts were the byproduct ..and probably a bit more shedding in the pan due to the added friction material in the fluid. Not trying to post in my usual cynical style, where did the divergence serve both GM and MOPAR where one fluid served both for decades? What freedom of design was enabled? This, at least in MOPAR's case, did not prove to be a wise move. They wrote the book on auto transmission paranoia where none existed before.
 
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 Originally Posted By: Whitewolf
Having said that here are some results that you might find interesting. What we're talking about is viscosity loss at the end of a 40 hr KRL:- DEXRON(R)-VI, 6.3% ATF +4, 20.2% MERCON-V, 26.3%
What this shows regarding ATF+4 is how linear it shears. KRL after 20 hours was 10%. After 40 hours 20.2%. A flat line (linear) shear rate is an indication of shear stability. Those number also show that Mercon V's shearing is not linear, with the vast majority of it occurring within the first 20 hours of the test: KRL after 20 hours, 19%. After 40 hours, 26.3%.
 
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The divergence arises due to the selection of friction materials and control system designs/calibrations. Any friction system is (at minimum) a combination of friction material, reaction surface, fluid and control system
 
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 Originally Posted By: Whitewolf
What you are observing is the effect of the use of different molecular weight VMs at different treat levels.
Higher MW shears more?
 

Audi Junkie

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My $.02c about LG FM (black?) is it wore out and shifts got hard. Based on that and common sense, I'd NEVER try to modify-up the quality of an ATF, but I'll use non-spec ATF, like +4. fwiw, Valvoline ok's MerconV in Audi/BMW ZF (LT) trans, but it looks like junk next to ATF+4. Mercon V is FM'ed, right? OT- did anyone hear if Dex VI got approved as a PSF, and any info on the red Mercedes PSF? I've speculated it's ATF+4.
 
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Im also curious as to whether Dexron VI has recieved approval for use in P/S systems. GM uses it in there heavy duty trucks. One of our new 2009 heavy rescues states " use only Dexron VI" on the power steering reservoir. You would think it would be ok to use since most ATF is in the 7 range for viscosity and it shears in use. So take DEX VI at around 6 and it shears very little, one would assume no issues. Would be nice to hear a go or no on this one.
 
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DexVI should make an excellent PSF. If your system calls for it, use it. Other options are Redline D6 or Amsoil ATL.
 
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