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58furyman |
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Member Posts: 12 Location: Southern Ohio | Why use substitutes when Type A fluid is still available? Most of the 'big box' auto stores don't have it but smaller auto parts dealers and even convenience stores carry it. There is a convenience store about a mile from my house that has it. They get it for me by the carton. Some brands: Formula 100 Type A, Hicks Oils, Duquoin, IL 62832 Quality Type A, Quality Foods Co-Operative, Inc., Elon Industrial Park, Lynchburg, VA 24506 Empire Type A, Warren Unilube, Inc., West Memphis, AR 72301 1-800-428-9284 LDCH Type A, LDCH Industries, South Bend, IN 46624 Just to name a few. Larry S. | ||
59CRL |
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Expert Posts: 2679 | 58furyman - 2010-07-18 11:13 AM Why use substitutes when Type A fluid is still available? Most of the 'big box' auto stores don't have it but smaller auto parts dealers and even convenience stores carry it. There is a convenience store about a mile from my house that has it. They get it for me by the carton. Some brands: Formula 100 Type A, Hicks Oils, Duquoin, IL 62832 Quality Type A, Quality Foods Co-Operative, Inc., Elon Industrial Park, Lynchburg, VA 24506 Empire Type A, Warren Unilube, Inc., West Memphis, AR 72301 1-800-428-9284 LDCH Type A, LDCH Industries, South Bend, IN 46624 Just to name a few. Larry S. I would need to look harder, the local autozones and advance auto dont have Type A. Im using Dexron in my torqueflite and it seems to work well. | ||
Fanbladeus |
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Expert Posts: 1218 Location: Warren, Michigan | I guess I'm not sure what the quality is of those type A fluids. I found a case of it at my local dollar store and put it in my old transmission. It was an odd color/smell from the beginning. I only drove the car around the block on that stuff. I had a rebuilt trans waiting in the wings and ended up putting that in before I could see what that junk stuff would do. Is the stuff you're talking about better that what I've seen? Does it looks, feel, smell like modern trans fluid? | ||
59CRL |
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Expert Posts: 2679 | Fanbladeus - 2010-07-18 12:28 PM I guess I'm not sure what the quality is of those type A fluids. I found a case of it at my local dollar store and put it in my old transmission. It was an odd color/smell from the beginning. I only drove the car around the block on that stuff. I had a rebuilt trans waiting in the wings and ended up putting that in before I could see what that junk stuff would do. Is the stuff you're talking about better that what I've seen? Does it looks, feel, smell like modern trans fluid? How did your trans shift and act with the type A you found? | ||
58furyman |
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Member Posts: 12 Location: Southern Ohio | I used DexronII in one trans. rebuild an and Type A in another and did not notice a difference in shifting. Took one car to Detroit (7 hour drive, one way) and the other to Carlisle (about 10 hours, one way) and didn't notice difference in fluid colors or odors. I've since sold those cars and haven't heard of any problems. I have another torqueflite that is going to get rebuilt in the near/distant future. I am going to use the Type A as the only fluid and see how it does. According to the various distributors web sites, the type A is supposed to meet original specs (less the original whale oil I would think!). Larry S. | ||
57plymouth |
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Expert Posts: 3577 Location: Blythewood, SC | Just use Dexron/Mercon. Don't waste half of your life looking for Type A. Many people here have used Dexron/Mercon for years with absolutely no ill effects. | ||
59savoy |
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Expert Posts: 2338 Location: central oklahoma! | what's the difference between type A and type F? | ||
d500neil |
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Exner Expert 19,174 posts. Neil passed away 18 Sep 2015. You will be missed, Neil! Posts: 19146 Location: bishop, ca | Type F was specifically formulated for Farts (like 'A' was, for Mopes???), and it is generally accepted as being too abrasive for our car's trannies, but, the 'F' will provide some harsh/sure shifting , which ordinarily is to be preferred over a soft/slow/comfy shift , and it might prolong the life of a failing transmission, by virtue(?) of its abrasiveness. 'F' is claimed to shorten the working life of our cars' transmissions. Our cars' trannies can be built to provide a 'hard' shift, without having to add-in the Type F Time-Bomb to the equation. | ||
57chizler |
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Expert Posts: 3776 Location: NorCal | Tell us, Neil, just how much could one expect to have the working life of our cars' transmissions shortened when using type F? Could you express that in an exact number of miles or a percentage? | ||
big m |
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Expert 5K+ Posts: 7806 Location: Williams California | Type A fluid was superceded by Type A-Suffix A in the early sixties, then superceded by Dexron, DexronII and Mercon. Any or all of these meet the specifications ot the early torqueflites, I have heard of folks using the Type-F for better shifting, but I'll stick to the specified fluid. Also, beware of cheap fluid sold in gallon containers as it may be reconstituted or recycled fluid. These usually will have an odd smell to them. ---John | ||
d500neil |
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Exner Expert 19,174 posts. Neil passed away 18 Sep 2015. You will be missed, Neil! Posts: 19146 Location: bishop, ca | Heh, heh, John, I said "claimed"... Your mileage, before disaster strikes, may vary! | ||
59CRL |
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Expert Posts: 2679 | d500neil - 2010-07-19 4:31 PM Type F was specifically formulated for Farts (like 'A' was, for Mopes???), and it is generally accepted as being too abrasive for our car's trannies, but, the 'F' will provide some harsh/sure shifting , which ordinarily is to be preferred over a soft/slow/comfy shift , and it might prolong the life of a failing transmission, by virtue(?) of its abrasiveness. 'F' is claimed to shorten the working life of our cars' transmissions. Our cars' trannies can be built to provide a 'hard' shift, without having to add-in the Type F Time-Bomb to the equation. So if I bought a Fartmobile I should use type "fart" fluid in my fartmission?? Maybe an addition of too much corn and peanuts made the fluid too abrasive.... I will add a bottle of Beano and see what happens, thanks for the info! Edited by 59CRL 2010-07-19 8:36 PM | ||
d500neil |
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Exner Expert 19,174 posts. Neil passed away 18 Sep 2015. You will be missed, Neil! Posts: 19146 Location: bishop, ca | You're probably on the wrong website for advice on the application of type F fluid, for the Farts...but Beano may well be a recommended performance-enhancing additive for them. | ||
59CRL |
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Expert Posts: 2679 | d500neil - 2010-07-19 8:46 PM You're probably on the wrong website for advice on the application of type F fluid, for the Farts...but Beano may well be a recommended performance-enhancing additive for them. Exactlly!! The advice I was looking for Beano!!!! | ||
big m |
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Expert 5K+ Posts: 7806 Location: Williams California | d500neil - 2010-07-19 1:31 PM Type F was specifically formulated for Farts (like 'A' was, for Mopes???), and it is generally accepted as being too abrasive for our car's trannies, but, the 'F' will provide some harsh/sure shifting , which ordinarily is to be preferred over a soft/slow/comfy shift , and it might prolong the life of a failing transmission, by virtue(?) of its abrasiveness. 'F' is claimed to shorten the working life of our cars' transmissions. Our cars' trannies can be built to provide a 'hard' shift, without having to add-in the Type F Time-Bomb to the equation. Neil, just to clarify, Type F fluid was not introduced until the mid sixties, prior to that, Ferd specified Type A fluid for its automatics as well. ---John | ||
d500neil |
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Exner Expert 19,174 posts. Neil passed away 18 Sep 2015. You will be missed, Neil! Posts: 19146 Location: bishop, ca | Well, since your "M" is of some consequence, what did the Fartster do to its trannies, to require a more abrasive oil formulation to be used in them? | ||
57chizler |
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Expert Posts: 3776 Location: NorCal | I have a problem with the use of the word "abrasiveness", just because a particular fluid is less "slippery" than others doesn't make it abrasive....abrasive is generally used to describe something that promotes wear. While type F is slightly less efficient at preventing wear it is, by no means, abrasive. Water will eventually wear away rock (see Grand Canyon) but you seldom, if ever, see water described as being abrasive. Edited by 57chizler 2010-07-20 5:41 PM | ||
big m |
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Expert 5K+ Posts: 7806 Location: Williams California | d500neil - 2010-07-20 12:20 PM Well, since your "M" is of some consequence, what did the Fartster do to its trannies, to require a more abrasive oil formulation to be used in them? The introduction of the lighter C-6 and C-4 transmissions was the reason for the creation of type F. I was not involved in the engineering process, so I cannot tell you why, though. ---John | ||
56royaldodge |
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Account deactivated by owner's request Location: On this barrel | I'm wondering if a type A personality would loose sleep over their transmission fluid? | ||
Chopper John |
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Expert Posts: 1488 Location: Florida | Maybe so, but there are certainly a few Type "F" personalities around here! And they CAN be abrasive! | ||
56royaldodge |
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Account deactivated by owner's request Location: On this barrel | |||
d500neil |
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Exner Expert 19,174 posts. Neil passed away 18 Sep 2015. You will be missed, Neil! Posts: 19146 Location: bishop, ca | Everything is relative, and it is (still) my understanding that type F transmission fluid is more abrasive than is either Type A or the current Dexron-Mercon formulation, and that Type F is not a recommended application for our cars, as it will (significantly) reduce the operational life of our cars' transmissions. | ||
57chizler |
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Expert Posts: 3776 Location: NorCal | Well, again, I have to disagree with Neil's assessment. The word abrasive is totally out of place in a discussion of ATF, type F has a slightly more aggressive coefficient of friction which will mean less slippage and therefore less heat buildup; it also has the benefit of a more potent detergent which helps prevent the buildup of varnish. Making a claim that "Type F is not a recommended application for our cars" begs the question, not recommended by who? The claim that it will "significantly" reduce life also begs proof. All jokes aside, I don't see an epidemic of Ford failures, in fact you'll find lots of units that go as many miles between overhauls as other brands. | ||
Fanbladeus |
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Expert Posts: 1218 Location: Warren, Michigan | I only have a few thousand miles on my rebuilt torqueflite and I use type F. It still works amazingly well. The advice to use type F was from the Chrysler 300 club, so I guess someone there must recommend it. I'm going to continue to use it and in about 15 years I'll let you know if I have any problems. | ||
d500neil |
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Exner Expert 19,174 posts. Neil passed away 18 Sep 2015. You will be missed, Neil! Posts: 19146 Location: bishop, ca | It'll be sooner than that. I've got no vested interest in whether a person smokes cigarettes, drinks heavily (but doesn't drive) or puts Type F trannie fluid in his MoPar. The parachutist whose chute has failed can only say :"So far, so good!". Edited by d500neil 2010-07-22 6:16 PM | ||
57chizler |
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Expert Posts: 3776 Location: NorCal | Tell ya what, neil, instead of repeating the same old droll platitudes why not bless us with a dissertation on why the iron TF will fail sooner when using type F? Don't hold back, give us a thorough overview by comparing the makeup of the various internal components such as clutch/band composition, bearing/bushing material, seal material, etc. with a Ford product that uses type F. Don't be afraid to get real technical, they don't charge by the word here. I'll wager that what we really get is an anecdotal tale such as "My uncle's brother in law's kid .........". | ||
58furyman |
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Member Posts: 12 Location: Southern Ohio | Being as I can get as much as I need less than a mile from here, I don't think that I'm wasting too much time. It's out there, if you look around. Just depends on what you want to use. Larry S. >Don't waste half of your life looking for Type A.< | ||
MOPAR-TO-YA |
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Expert 5K+ Posts: 5139 Location: cornpatch county, Southwest IOA | Why use any oil that is hard to find when you are on a trip? On a Sunday, the only place that is open is a convienience store and they all have the tryed and proven Dexron III-Mercron. Same goes for motor oils with ZDDP. Use a good brand , easily found, and a little bottle of ZDDPlus additive---no problem. You don't need no stinking raceing oil or specially formulated expensive hard to obtain stuff!!......................................MO | ||
zrxkawboy |
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Veteran Posts: 168 Location: SD | As mentioned by 57chizler, it's the coefficient of friction that differs. Type F has no friction modifiers (which allow some slippage, therefore a slightly "softer" shift). Dex/Merc has a small amount of friction modifiers, while a modern HFM (highly friction modified) ATF like ATF+4 has a relatively high dose. On older trannies, one can somewhat tailor the shift feel to their preference by their choice of fluid. As mentioned, Type F in a TF will give a firmer shift than Dex/Merc. (Though I'm no trans expert, I would think it may even INCREASE the life of the trans, due to less slippage during the shift, though this effect would probably be minimal.) If the shift is a little too firm for your liking, you could certainly experiment with different ratios of Type F:Dex/Merc, until you got the shift feel where you wanted it. All that being said, most owners (and their trannies) would probably be perfectly happy with any quality Dex/Merc. Edited by zrxkawboy 2010-07-24 11:23 PM | ||
1960DesotoAdventurer |
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Expert Posts: 3588 Location: Plymouth Spaceport | Years back at an estate sale I found a vintage late 50's bottle of Type A Trans fluid and it was yellow in color and had an unusual smell..I guess this was the type with whale oil. I just use the Dexron/Mercon fluid as BigM and others have suggested and have never had a problem. Edited by 1960DesotoAdventurer 2010-07-25 2:30 PM | ||
57chizler |
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Expert Posts: 3776 Location: NorCal | All ATF is colorless after leaving the final refining process, colored dye is added by the refiner to identify it; red is the most common but some brands use different colors...Chevron, for example, dyed their Type F fluid blue for many years. After snooping around various message boards over the years I have seen a wide variety of recommendations for fluid in the Chrysler Torqueflight, among them are type A, Dexron (all variations), type F, ATF+ (all variations), John Deere spec transmission fluid and even AW-32 hydraulic oil. Each and every user swore by their choice and reported "no problems". Go figure. | ||
John Serkaian |
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Regular Posts: 62 Location: Novi, Michigan | Before electronic controls became common in automatic transmissions, it was either GM Dexron/Type A fluid or Ford's Type F. Type F offered a higher static coefficient of friction which could help shorten shift times and provide better clutch capacity for a given apply force while Type A and Dexron fluids had different additive packages (Lubrizol was the big player at the time) that offered a more "slippery" characteristic to help shift feel at the expense of more slippage. (The infamous GM "whale oil" additive was simply a synthetic additive to reduce friction. I had a limited slip differential in a mid-70's GM vehicle that wouldn't release at low speeds and driving in the snow or rain became very interesting with a locked differential. The additive lowered the static coefficient of friction to break loose the clutch pack during turns.) Balancing the static and dynamic friction characteristics to prevent noise and "shutter" (slip-stick instability) was a problem then and it remains a problem today with the many various clutch linings and their "special" patterns as well as different fluids and additive packages. Today's fluids are "slippery" with additives to keep solenoids and other electronic controls happy at low temperatures. Older transmissions should function fine with any modern transmission fluid while aftermarket synthetic fluids might run a little cooler and have higher friction characteristics for shorter/harsher shifts. I'd do some consulting with vendors offering replacement transmissions as well as the vendors who produce clutch packs and transmission re-build kits to see what they recommend for their friction linings and decide for yourself what would work best for your purposes. Good luck. | ||
Shep |
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Expert Posts: 3393 Location: Chestertown, NY ( near Lake George) | I put 500 1/4 mile 9 sec passes on my 68 Hemi Dart back in the day, and used Dexron with no internal failures. | ||
MOPAR-TO-YA |
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Expert 5K+ Posts: 5139 Location: cornpatch county, Southwest IOA | Shep - 2010-07-26 11:53 AM I put 500 1/4 mile 9 sec passes on my 68 Hemi Dart back in the day, and used Dexron with no internal failures. THERE!-- top that type F ! ..............................MO | ||
John Serkaian |
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Regular Posts: 62 Location: Novi, Michigan | I spoke with Ford's ATF oil "expert" and got some interesting insight on current and past oils. The bottom line is you can't go wrong with Type F for any older transmission. Avoid the latest Dexron fluids due to the additives attacking some seal materials. (Allison learned the hard way three years ago.) Mercon 5 can replace older Dexron/Type A specifications as it has good friction modifiers for smooth shifts and it doesn't attack seals. Ford also monitors the aftermarket to insure Mercon oils meet Ford quality standards. Type F is as pure as it gets for transmission fluid as it has no friction modifiers. However, Ford no longer sells Type F and they don't monitor what the aftermarket is producing under the Type F label so stick with a reputable brand oil if running Type F. I'd assume the same goes for anything sold under the Type A label. Who knows what's really in it if it's from someone outside the normal OEM supply chain? Also, stay away from anything sold as a universal ATF for older transmissions - again, no one knows what's really in them and they are not controlled under any real specifications. This could all be academic as a transmission either has enough clutch capacity to handle the input torque from the engine (X 2 after going through the torque converter) or it doesn't. What ATF you use won't change that and it might not even affect shift quality on 2-speed or 3-speed transmissions utilizing very simple and easy to calibrate non-synchronized shift events. (The newer 4-speed through 8-speed automatics are another story and calibrations and friction materials are more sensitive to ATF selection.) I'll see if Chrysler still has an ATF "expert" and see what their take is on a modern oils and a Type A replacement. Same goes for GM. Stay tuned... | ||
1959 Belvedere Conv |
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Elite Veteran Posts: 1107 Location: Arvada, Colorado (NW Denver Metro Area) | John S., I will send a E Mail to Octie Ham (Lake Orion,. MI) of the 59 Plymouth Forum (www.59Plymouth.net) to see what he thinks. (don't know if he frequents the FL site) He worked in Chryslers Drive Train at Highland Park and Auburn Hills before retiring. I just saw him at Carlisle this year. I worked in stamping and later district sales, so I am of no value to this thread but would love to learn more about the acceptable fluids for TF's. | ||
d500neil |
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Exner Expert 19,174 posts. Neil passed away 18 Sep 2015. You will be missed, Neil! Posts: 19146 Location: bishop, ca | There's a couple interesting Internet articles that hopefully, that Big M can post up here, for me.... | ||
big m |
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Expert 5K+ Posts: 7806 Location: Williams California | Here are the links from Neil- http://www.aa1car.com/library/atf.htm http://www.mobiloil.com/USA-English/MotorOil/Other_Products/Mobil_T... | ||
d500neil |
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Exner Expert 19,174 posts. Neil passed away 18 Sep 2015. You will be missed, Neil! Posts: 19146 Location: bishop, ca | Thanks, John; y'all did/do read the second link, from Mobil-1, right????? Mercon 'merged' with Dexron, IIRC, and their new corporate name is Dexron-Mercon IIRC. Dexron III is the ATF of best application for our cars, and it's almost certainly better formulated than the old-pure Type A ATF ever was (except, possibly, for its association with 'whales'...LOL). The bottle's label is DexronIII/Mercon, but it's the "Dexron III" which is important to look for. Edited by d500neil 2010-07-31 2:08 PM | ||
57chizler |
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Expert Posts: 3776 Location: NorCal | d500neil - 2010-07-31 10:25 AM Dexron III is the ATF of best application for our cars, Says who? One thing ya gotta remember, the makers of any product will be very conservative in their recommendations due to the legal establishment. Just because a refiner doesn't specify a certain usage doesn't mean it's not appropriate. Remember, the latest versions of Dexron are formulated for transmissions with lockup converters and overdrives, these units have unique requirements compared to older ones. When was the last time you heard somebody complain about lockup clutch chatter or short planetary life in an iron Torqueflight? | ||
d500neil |
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Exner Expert 19,174 posts. Neil passed away 18 Sep 2015. You will be missed, Neil! Posts: 19146 Location: bishop, ca | Mobil-1 MAKES/sells Type F; it would have no vested interest in not telling the truth about what NOT to put into our trannies. | ||
Fanbladeus |
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Expert Posts: 1218 Location: Warren, Michigan | Did I miss something in those atricles where it mentions our cars or type A? I guess I can re-read them but I must have missed it. | ||
1960DesotoAdventurer |
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Expert Posts: 3588 Location: Plymouth Spaceport | has anyone here had Dexron 3 attack their seals and cause leaks? I was unaware it was reformulated,can anyone shed light on this?...do I need to worry? | ||
Mopar1 |
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Expert Posts: 3033 Location: N.W. Fla. | Some years ago I saw results of various specs involving F & Dextron. Don't remember the details but @ the time F came out as superior in all the categories. Puzzling where Ford went to Dextron in the late 70s(more or less). | ||
1960DesotoAdventurer |
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Expert Posts: 3588 Location: Plymouth Spaceport | So far I havent had to add any more trans fluid to my DeSoto or Plymouth,but I would hate to use the wrong thing and wind up ruining the seals. I had always used Dexron in the past in my Forward Look vehicles and never had the leaking problem...when did they reformulate dexron 3? | ||
57chizler |
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Expert Posts: 3776 Location: NorCal | d500neil - 2010-07-31 4:50 PM Mobil-1 MAKES/sells Type F; it would have no vested interest in not telling the truth about what NOT to put into our trannies. Nowhere in their sales pitch does it tell you not to put it in certain units, it merely tells what it is intended for. Once again, if they were to say their fluid is OK for the iron Torqueflight and a unit failed from a problem that was not fluid related some "the sky is falling" individual like you would be all over the internet accusing them of false advertising. | ||
57chizler |
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Expert Posts: 3776 Location: NorCal | Mopar1 - 2010-08-01 10:12 AM Puzzling where Ford went to Dextron in the late 70s(more or less). They went to Dexron about the same time lockup converters arrived, type F is not what you want to use with a lockup converter. All of the "upgrades" to Dexron like II, III, Mercon were to make the fluid compatible with lockup converters and overdrives. Ditto for the Mopar fluids, 7176 replaced Dexron and 7176 became ATF+2, +3, +4 to make them more friendly to modern lockup overdrives. | ||
zrxkawboy |
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Veteran Posts: 168 Location: SD | The latest Dex fluid is Dex VI. It is lower viscosity, but more shear-stable. I don't think I'd use it in an old Chrysler trans, but it may be fine. GM no longer licenses Dex III, so that's why the current labels say things like " for use in Dex III applications". Since there are no regulations for the quality of these fluids (ie, GM doesn't license Dex III, so no one is "policing" the mfrs), I'd stick with well-known brand names. | ||
1960DesotoAdventurer |
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Expert Posts: 3588 Location: Plymouth Spaceport | big m - 2010-07-19 6:12 PM Type A fluid was superceded by Type A-Suffix A in the early sixties, then superceded by Dexron, DexronII and Mercon. Any or all of these meet the specifications ot the early torqueflites, I have heard of folks using the Type-F for better shifting, but I'll stick to the specified fluid. Also, beware of cheap fluid sold in gallon containers as it may be reconstituted or recycled fluid. These usually will have an odd smell to them. ---John So Dexron II is the best fluid to use in our cars transmissions then,not Dexron III? I looked at the link you posted for D500Neil and it says the Dexton III is for electronic transmissions. I am going to probably change the fluid on my plymouth torqueflite soon and want to use the best stuff. | ||
mikes2nd |
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Expert 5K+ Posts: 5006 | I think the latest Dexron is the best, it has been improving and still compatible with dex 2/3... The original Dexron transmission fluid was introduced in 1968. Over the years, the original Dexron was supplanted by Dexron-II, Dexron-IIE, Dexron-III, and Dexron-VI, which is the current fluid. GM has upgraded the Dexron specifications over the years; newer fluids are generally but not always backward compatible with previous fluids. Because there are still applications for which Dexron-VI either has not been proved suitable or deemed to be not necessary, there remains a market for fluids that claim to meet the earlier specifications. DEXRON[edit] The original Dexron fluid, like its predecessor Type-A/Suffix-A, used sperm whale oil as a friction modifier. The U.S. Endangered Species Act banned the import of sperm whale oil, so the fluid had to be reformulated.[1] DEXRON-II, IID and IIE[edit] Dexron-II was introduced in 1972 with alternative friction modifiers such as Jojoba oil. However, it caused problems with corrosion-prone solder in GM's transmission fluid coolers;[2] accordingly, corrosion inhibitors were added to the product. The resultant fluid, released in 1975, was called Dexron-IID. However, the corrosion inhibitor made the new fluid hygroscopic, which while it was not a major problem in automatic transmissions, made Dexron IID unsuitable for other hydraulic systems in which it was commonly used.[2] A further reformulation, to address excessive hygroscopicity[citation needed], but primarily to improve low temperature performance (20,000cP @ -40C vs 50,000cP@-40C for Dexron-IID) was named Dexron-IIE (GM Spec GM6137M). DEXRON-III[edit] In 1993, GM released new Dexron-III fluid (GM Spec GM6417M and later GMN10055). It is generally backward-compatible with transmissions using earlier Dexron fluids or Type-A/Suffix-A fluid. However this specification failed to address a number of issues concerning long term durability such as shear stability and fluid oxidation. Dexron-III underwent a number of iterations in an attempt to address various shortcomings but was eventually replaced by new thinking i.e. DEXRON-VI. DEXRON III G[edit] Dexron III G was a synthetic automatic transmission fluid, especially developed for new (after 1997) and older (automatic) transmissions build by Ford and GM, as well as for many other brands. It is also suitable for power steering systems, some hydraulic systems and for rotary air compressors where an excellent low temperature fluidity is required. DEXRON III H[edit] Introduced in 2003, replaced III G. The H is an additive package for an updated friction modifier, and with an oxidatively stable base oil (group 2 or group 3). Oils according to this specification have longer maintenance of friction properties and anti-shudder properties, better foam control and a longer fluid life. Universal for all automatic transmission with and without controlled torque converter lockup clutch, the so called GKÜB for gear-clutch-lock. DEXRON-IV An attempt to introduce an 'upgrade' that was not fully accepted by GM management for a number of reasons including the way that it was promoted internally and cost. It was therefore abandoned in favour of making further incremental upgrades to the existing DEXRON-III specification. DEXRON-VI[edit] The fluid specification for Dexron-VI was introduced in 2005, and was first used as the GM factory-fill automatic transmission fluid for model year 2006. All Dexron-III licenses expired permanently at the end of 2006, and GM now supports only Dexron-VI fluids for use in their automatic transmissions,[3] although fluids asserted by their manufacturers to meet Dexron-III standards continue to be sold under names such as Dex/Merc. These fluids are not regulated or endorsed by GM.[4] Dexron VI is of a slightly lower viscosity when new compared to the prior Dexron fluids (a maximum of 6.4 cSt at 100 °C for Dexron VI and 7.5 cSt for Dexron III), but the allowed viscosity loss from shearing of the ATF during use is lower for Dexron VI, resulting in the same lowest allowed final viscosity for both Dexron III and VI (5.5 cSt) in test.[5] In reality most of the DEXRON-III fluids typically sheared to about 4.2 cSt in use. The lower, more stable viscosity improved pumping efficiency within the transmission and fluid stability over life. Since Dexron VI is not allowed to thin out (lower its viscosity) as much as Dexron III during use, it requires the use of higher-quality, more shear-stable (less prone to thinning while in use) formulations.[4] The current GM specification that defines the fluid is GMW16444, which superseded the original specification, GMN10060 | ||
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