Joined: Wed Aug 11 2010, 10:15AM
Location: E WA
Posts: 1230
furyfever wrote ...
I'm re-filling my transmission with fluid after replacing filter and pan gasket....68 Dodge Monaco 500...Manual says to put in:
AQ ATF Suffix-A (Dexron)
Well that was a long time ago obviously...Dexron I...Dexron II...Dexron III have all come out since then...and now of course there's Dex-Merc...Is that the right stuff to put in now-a-days?
Thanks, Bob
I put Mobil 1 ATF in the trans in my 69 LeBaron about 10 years ago and the car shifts beautifully. My guess is that with the low miles I drive this fluid will never have to be changed.
Transmission Fluid is like Dirty Dish Washing Water - after a while it is still making some bubbles - but it is now very dirty with chunks of food matter in it.
The FSM Maintenance Chart in every issue says nothing about brands. They all say about lapsed time or miles used ( with Towing or HD Usage being noted as important ).
Joined: Tue Sep 07 2010, 08:49AM
Location: San Diego, CA
Posts: 218
Automatic Transmission Fluid.
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This is a troubling topic.
First, the original transmission fluid specified for our cars is no longer made.
One reason for this is that those transmission fluids contained whale oil.
Today, this is too politically incorrect for a ten-foot pole, or the planet earth. Dexron was invented as the first politically correct transmission fluid. It was actually a specification. The specification became more and more rigid over time: thus Dexron I, II, & III. There is no reason not to prefer Dexron III over II or I. However, I would stay away from Dexron IV in a vintage automobile. -
I called Coast Transmission, in Costa Mesa, California. [That is a recommendation.]
They said that they stocked two transmission fluids.
I think they said ‘Mercon’ for Fords and ‘Dexron III’ for the rest of us.
These guys are old school, they actually fix, rather than replace, transmissions.
If it is good enough for them, it is good enough for me.
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There are two difficulties here.
First, the word ‘Dexron III’ is trademarked and the word has been removed from the market.
It was a standard, if the product met the standard, the word ‘Dexron III’ was licenced to be used. Today, if someone put the word 'Dextron III' on a can, they could be put into prison. So they have to say 'Dextron III' in some indirect way such as "Dex/Merc".
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Second, has Ford relented?
I see words like ‘Dexron/ Mercon’ in large letters identifying the product.
This is really confusing.
I am assuming that this equivalent to Dexron III
The small print implies this.
You are more likely to get a good price if you are looking for a mainstream product.
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Why not Dexron IV?
I think that this product diverges from the ideal product for vintage transmissions.
Dextron IV is designed for newer [econo-crazy] transmissions.
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I have always been partial to Pennsylvania-based lubrication products.
I figured that Pennsylvania oil stock was somehow superior.
But that was half a life time ago.
Quaker State, Pennzoil, Kendall, Valvoline.
These companies than been sold so many times that is it difficult to tell "Who is on third?"
Quaker State is now owned by Pennzoil, headquartered in Houston, and together owned by Royal Dutch Shell.
I had made Valvoline, headquartered in Kentucky, RJ’s official oil.
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Valvoline can be a price leader.
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I have three, more than 45-year-old, vintage cars, including 1976 Chrysler Newport, 1966 Cadillac sedan de Ville, 1970 Chevy C-10 Pick up.
Now Valvoline has a ‘MaxLife’ line for older [75,000 miles] cars.
My 1966 Cadillac, only has about 30,000 miles, so technically it is too new for older [75,000 miles] car MaxLife oil.
But I am very worried about my seals, so I think that MaxLife has good stuff for seals. So I am using it in the Cadillac anyway.
- Now I use a lot of transmission fluid. To go after a rare specialty fluid, with the word Chrysler on the can, is triple as expensive, and IMHO unnecessary. For me it would be just throwing a lot of money away for no reason. - How bad is it, RJ?
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I think that in order to actually move the 67 Chrysler, or the 70 Chevy C-10 pickup,
I would have to add a quart of transmission fluid to each.
The fluids just disappear over the months. The seals dry up.
So I will be needing many quarts of transmission fluids, perhaps even gallons, in one year.
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Going for bulk.
More surprises.
Buying a 55-gallon drum, for $1,300, actually cost more per quart than purchasing a lessor amount.
Perhaps the 55-gallon steel drum is an extra expense.
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The five gallon buckets seem inconvenient, and the savings is not enough to justify the hassle.
[The case of 12 quarts is another venue, but I have not run into many of these.]
I think that the gallon sized is the best deal, and extremely convenient compared to other venues.
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Obviously, this thread will always be a work in progress.
But here is my plan.
I have purchased a couple of gallons of Valvoline MaxLife Dexron/Mercon Automatic Transmission Fluid.
The best price that I have found for a gallon container is $16.97 at Wall Mart.
This is $4.24 a quart. That is the gauntlet.
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Big Problem here:
‘Out of Stock Online’.
‘In Limited Stores’
‘Check for store availability’ - I selected this and entered my zip code.
The nearest store where this was available is 100 miles away.
However, it is on the route to where the three of my vintage cars are parked, and they are open 24 hours.
Joined: Wed Dec 21 2005, 07:34AM
Location: indiana
Posts: 791
Gonna post in this old thread, it might be book-length but it might be a worthwhile read for some of you.
In a past life I worked as a transmission test engineer during a period when Dex 6 was being evaluated for introduction and also during a validation of a synth fluid from an alternate vendor.
Oil specs: As mentioned, transmission fluid types are created to meet a spec, and that spec contains minimums and maximums for a variety of performance and wear characteristics. The oil companies refine the base oil and then buy an additive package from a chemical company. The additive is almost completely what determines the character of the oil and the base oil is practically useless and ‘fragile’ without an additive. There is a balancing act amongst parameters (anti-wear, anti-foaming, seal preservation, oxidation, friction, etc) and the add-pack can be adjusted to hit a ‘sweet spot’. End result - different brands of oil that meet the same spec could provide slightly different performance characteristics. Some components of an additive package are more expensive, so it is possible that an oil blender can cheapen his spec to the chemical house to meet an oil spec and then his oil’s performance will be inferior in some area (such as oxidation resistance?). Still meets spec, though.
Dex 6: Back when it was first being tested, it was tested only to a standard test spec. As transmissions were becoming significantly more durable than when the test stds were created, some longer testing was done to probe long-term durability. What was noticed after a while was that Dex 6 units tended to show some seal leaks that synthetic-oil transmissions didn’t. Chemical analysis showed that the Dex6 contained a component that provided some additional ‘curing’ of certain seal components, however it tapered off during the fluid’s life and caused no issues. However, if doing a flush-fill the fresh fluid would cure those seals further, which reduced their pliability and caused cracks and leaks. Generally the seals that leaked were of less-expensive material (ie lower heat resistance). Reformulate the oil or reformulate the seal? There’s that cost-benefit balance again…
That was a handful of years ago, before any of us had even heard of Dex6, and it took someone to notice a mild trend and chemical and microscope analysis to find the cause. Maybe it’s been fixed, maybe not (ala the infamous ignition switch). None of us could ever know. And if you did a flush/fill on a 10-year-old car and then a year later got a seal leak, how could a layman attribute it to new oil???
Synth oil: Validating an alternative synth oil was a multi-year project. Numerous tests were run, components inspected, and the oil formula was tweaked afterward (then all was repeated). At the end of the test differences could still be seen between oils, but those differences required a keen skilled eye and the support of chemists and microscopes. Oh, and they depended on back-back tests run under similar repetitive test conditions.
1 rule we saw repeatedly upon disassembly of test transmissions – those run with synthetic fluid were cleaner on the inside and had less wear on *all* the components. It was a significant difference and it was visible in every subassembly of the transmission.
So my point – there’s a lot involved in formulating an oil to meet a certain transmission manufacturer's spec, there’s variation amongst oils that meets those specs, and to know the difference would require far more data than any of us (even a transmission rebuild shop!) would ever be able to attain as John Q Citizen. Even if you were savvy on that and did a lot of pre-post rebuilds (of a fleet of transmission), there would be so many other variables (driving habits, vendors supplying your components, mfgs supplying the vendors, etc) that it would be hard to make any stone-certain conclusions. It doesn’t stop people from making vehement keyboard conclusions, though.
So use whatever oil you wish, just make sure it has an API label on it, and most likely you won’t drive hard enough/long enough for it to make a difference in long-term durability.
Here's the way i look at it. When you go to the store and grab ANY bottle of fluid,it will be a lot better than ANY premium fluid you could get on the shelf in 1969. If you have a trans with a lot of miles and the seals and gaskets are weak don't use synthetic or this will move past weak seals and the clutches will slip more because of the less friction properties of that oil. When i did my 727 i went with the Alto/Red Eagle clutches and Teflon seals and premium gaskets throughout. I ran the trans for a few months with the Type F for breaking in the clutches which i had done for years of no problems then i changed over to the Valvoline ATF+4. I use synthetics in all vehicles including the boat/sleds etc. I would not hesitate going back to the older style oils anyday!
Joined: Fri Mar 09 2007, 02:34PM
Location: Philadelphia
Posts: 661
You pretty much have to go with Dex-merc, as I do. I remember buying Dex III at walmart around 2006 or 2007 for $1.75 a quart, but I think it's not made anymore. Dex-Merc is the replacement, and afaik, all you can get except for Dex-VI. Unfortunately, trans fluid is like $5 a quart now. I work at an auto parts store, and we still carry type F, but I would never use it. As far as I'm concerned Type F should be extinct, just like all those crappy Ford automatics that slipped, like the FMX I had.
Joined: Sat Aug 19 2006, 05:03PM
Location: Ontario, Canada
Posts: 2919
Very interesting comments Chris (Fury Fan). I know that on other forums I've read, some commenters say that, if the fluid has not been changed on an older transmission then leave it alone because you're likely to do more harm than good. ie: Trans ran fine, owner changed the fluid, then it crapped out. I always thought that advice was bunk, but you just explained how it could have merit.
The only other thing is to just change (drain and fill) the fluid but not do an aggressive "flush" as some garages do, because it could dislodge deposits in the system which would then travel in the fluid and clog-up something important.
I had a 727 overhauled at SMR. The proprietor there said he's experimented with using ATF+4 (synthetic) and based on his results he has no use for synthetic fluid. He said to run a name-brand Dextron fluid along with a bottle of Molyslip ATS. Having said that, my pickup calls for ATF+3 which you can't get anymore so I run ATF+4 in that and never had any problems.
As for the non-availability of Dextron-III, that is a GM term, and GM stopped allowing vendors to use the term "Dextron-III". So now you'll see fluid that says something like "Use in transmissions formerly serviced by Dextron-III". AFAIK it's the same stuff, but they're not allowed to call it "Dextron".