roadmaster_56

Dynaflow info needed - drain plug torque + long term use of "Type F"

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I've looked in all my Buick repair books but I can't find the torque values for the two small 7/16" brass drain plugs in the torque converter of my '50 Dynaflow.....Does anyone know how tight to torque them?   I'd rather be safe than have to replace the torque converter due to over tightening/stripping.....

 

Also has anyone run straight" Type F" fluid in their ('50) Dynaflow.   I'm contemplating this because I've heard that "Type F" is closer to the original formulation that was used in Dynaflows.  Also heard that Dexron's composition has morphed over the years and creates more slip on acceleration, where Type F is "grippier".   Any long term problems with using "Type F"?

 

Thank you,

David in Santa Cruz

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I could be wrong, but thought that Type A was the originally correct fluid for Dynaflow

 

Any thoughts?

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Posted (edited)
45 minutes ago, Marty Roth said:

I could be wrong, but thought that Type A was the originally correct fluid for Dynaflow

 

 

That's true as far as I know.

 

1 hour ago, roadmaster_56 said:

I'm contemplating this because I've heard that "Type F" is closer to the original formulation that was used in Dynaflows. 

 

Thats a tough one. Dexron was the replacement for type A, and was backward compatible. Anything made now to be compatible with Dexron II or Dexron III or Mercon should be compatible. Unfortunately there are fluids now that are NOT backward compatible, but do have "Dexron" in the name. I don't remember at what version compatibility broke.

 

1 hour ago, roadmaster_56 said:

Also heard that Dexron's composition has morphed over the years and creates more slip on acceleration, where Type F is "grippier".  

 

There is a little truth in that. Ford automatics originally took Type A. In 1963, Ford introduced their own unique fluid (type F). It was a less slippery fluid, closer to plain oil. Ford then recommended it be used in all of their automatics back to the beginning. Back in my gas station days I heard that it was because 1963 and later Fords used asbestos linings on the bands and clutches, and needed something less slick than type A. Transmissions I have torn down seem to support this view, but I cant prove it so YMMV. My 1961 Ford which originally specified type A had brass/bronze linings in the clutches and some sort of phenolic paper lining on the bands.

 

My 1961 Ford had all sorts of transmission trouble and several failures, a lot of it related to sticking valves. I was using type F in it per Ford's recommendation. Family friends of ours had a 1954 Ford with a Ford-o-Matic that they had bought brand new. In the late 80s (at about 40,000 miles) they changed the fluid using type F. The transmission never worked properly again until they drained the new type F back out and put Dexron III (Mercon) in. If it were me I would not use type F in anything that did not absolutely require it, and that means Ford transmissions made from about 1963-1974 which have never been overhauled using more modern linings.

 

The Dynaflow, which relies more on torque converter action rather than clutches and bands for "shifting" Might not know the difference. I still wouldn't do it.

 

 

 

Edited by Bloo (see edit history)

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Posted (edited)

Marty:

That's true, but original Type A is hard/impossible to find and has been replaced by various iterations of Dexron.  I've heard that, unfortunately those changes in the formula are "further away" from the original than current "Type F" and make the Dynaflow less responsive, especially during acceleration.  Be interesting to know if anyone has tested this theory.  

 

Bloo: thanks for that info...I'm getting an education on  A, F, and Dex...

 

Another thought just occurred.....wonder if the tranny parts people at Fatsco might have some answers?

Edited by roadmaster_56
additions (see edit history)

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The original fluid for all automatic transmissions, back in the '50s was "Type A" fluid.  Probably similar to the hydraulic oil of the times, except for viscosity and additives which would make it a better "fit" for an automatic transmission.

 

Type F was a Ford-spec fluid from about '68 until into the later '70s, when they started to use Dexron-family fluids.  The difference in Type F and Dexron was their friction characteristics upon INITIAL clutch/band apply.  According to an article in "CAR LIFE" magazine, back then, Ford and GM were headed toward that desired "smooth shift", but went about it differently.  Ford designed their fluid for a more aggressive initial apply, but then put it with clutch material that was a bit "over-loaded, so that slippage would occur, by design, on that initial apply period.  GM went the other direction, putting in more frictional material capacity, then designing Dexron for a bit more slippage upon initial apply to compensate.  BUT once the frictional materials were fully applied, no slippage happened.  The only slippage was on the initial apply period, not afterward.

 

Many performance types would use Type F in their GM automatics, rather than Dexron, for a firmer shift.  Probably not unlike how the B&M Trick Shift atf acted, but for less money.

 

GM claims that any of their Dexron-family atf products are backward-compatible to their first automatic transmissions.  Even the current semi-syn Dexron VI fluid.

 

In the case of the DynaFlow, ANY fluid would probably work fine.  Type A fluid is still around, but you have to look for it.  The earlier Dexron fluid is still around too, normally as "Multi-Make" designated, so you have to read the back of the bottle to see if the main application is for GM products, rather than imports.  Dexrom VI is very available, but has a better longevity than any prior Dexron fluid.

 

Enjoy!

NTX5467

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Posted (edited)
On 5/26/2020 at 10:22 PM, NTX5467 said:

GM claims that any of their Dexron-family atf products are backward-compatible to their first automatic transmissions.  Even the current semi-syn Dexron VI fluid.

 

Are you sure about that? Wikipedia doesn't think so. Of course they could be wrong. I'm pretty sure I saw some mistakes on their Ford transmission fluid page.

 

Quote

Introduced in 2003, GM's Dexron III(H) specification (GMN10055) replaced III (G). The (H) is an additive package for an updated friction modifier and with an oxidatively stable

base oil (group 2). 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.

GM Dexron-III(H) licensed products prior to 2011 had a license number on the can that begins with the letter H. Example: H-30001.

NOTICE: This fluid specification and licensing program was Inactivated March 2011. The ATF Type III(H) fluid shown in the photograph is ACDelco's non-licensed fluid which is used to support older transmissions which still required the Dexron-III(H) fluid. This fluid is backward compatible with all previous Dexron fluids as well as the Type "A" Suffix "A", and the Type "A" fluids produced from 1949–1966.

 

But then this part is a bit contradictory..

 

Quote

All Dexron-III (H) licenses expired permanently at the end of 2011, and GM now supports only Dexron-VI fluids for use in their older automatic transmissions.

 

Quote

GM Dexron-VI(J) licensed products have a license number on the container that begins with the letter J. Example: J-60301. This was the first GM ATF to advertise 100,000 miles (160,000 km) between changes for "Normal Driving" conditions and 50,000 miles (80,000 km) for "Severe Service".[24] This fluid is backward compatible with Dexron-III(H) and Dexron-III(G) fluids only.

 

Then there is Dexron HP about which they said:

 

Quote

The rear panel label of early containers of this fluid incorrectly state that this fluid is backward compatible with previous Dexron ATF, it is not. The label was corrected on later bottles of the fluid.

 

And also Dexron ULV:

 

Quote

This fluid is not backward compatible with any previous fluids.

 

There are also 2 Mobil 1 products labeled Dexron, "black label" and "blue label" nothing said about backward compatibility there except they seem to be special purpose fluids. Also listed was Dexron III (K), a fluid for manual transmissions only.

 

Edited by Bloo (see edit history)
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All:

Certainly getting a lot of good history on Dexron, any advice on how much to tighten the  2 small brass drain plugs in the torque converter?

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Posted (edited)

I tighten until snug.  Then a 1/4 turn or less.  Sorry I do not know the ft pounds if there is any noted in a repair manual.   Use the Dexron.  I also use Lucas transmission stop slip.  It thickens the Dexron trans fluid.  It is to my understanding the newer Dexron fluids are thinner than the fluids used in the 50s.    It made a difference in my Dynaflow as it was losing prime after sitting a week following a complete transmission fluid change.    

Edited by avgwarhawk (see edit history)
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On 5/26/2020 at 9:39 PM, Bloo said:

If it were me I would not use type F in anything that did not absolutely require it, and that means Ford transmissions made from about 1963-1974 which have never been overhauled using more modern linings.

 

Same here. Dexron III/Mercon are very good. And what you don't use in the Dynaflow can be used as a rust lubricant! 😉 

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Posted (edited)

Not sure where the Wiki information was sourced.  I do know that GM has always claimed that Dexron VI is backward-compatible back to the first HydraMatic (1949 or so?).  They've never wavered from that.  BUT an interesting product appeared in the ACDelco Chemical/Fluid catalog a year or two ago, a "Dexron III-type" (non-syn blend) fluid appeared under a non-Dexron III name.  GM ceased to license Dexron III fluid when Dexron VI fluid came out.

 

The Dexron HP fluid, I believe, is a full-syn fluid that's designed more for the later 6+ speed automatics with lock-up torque converters (which they seem to modulate between non- and partial-lockup, in particular situations).  I believe there is a Mobil 1 variant of that, too?  The current syn fluid for GM automatics is about $45.00/gallon, or more.  NO real need for anything that fancy in a DynaFlow!  Or even anything with a higher-spec than the prior Dexron III fluid.  No operational need for Type F, either, fwiw.

 

I suspect that any Dexron-family fluid would have a much better additive package than ANY oil available when the DynaFlow was designed and built.  But no real need for anything "fancier" than Dexron III.  EACH of the Dexron-family variants, progressing through time from their initial introduction, had some particular issue they were seeking to address/fix/prevent, all the way to the end of Dexron III.

 

Much of the confusion can quickly dissolve when you limit the possible fluids to the pre-6 speed automatic time frame, fwd or rwd.  Which should pare things down to a "dino" or "synthetic" Dexron III-spec fluid.  OR, you can seek out some of the Type A Suffix A fluid that pre-dates any Dexron fluid.  Your judgment call.

 

See below.  Sorry for the poor "paste" functions.

 

Enjoy!

NTX5467

 

10-9243

Dexron VI Full Synthetic Automatic Transmission Fluid - 1 qt

ACDelco DEXRON-VI Full Synthetic Automatic Transmission Fluid is the most recent release in the well-established DEXRON series of automotive transmission fluids. It provides more consistent shift performance, even in extreme conditions, and degrades less over time. ACDelco DEXRON-VI Full Synthetic Automatic Transmission Fluid helps automatic transmissions last longer and perform better. ACDelco DEXRON-VI Full Synthetic Automatic Transmission Fluid is suitable for use in vehicles that specify the following requirements: fully licensed and approved by GM, recommended for use in GM transmissions model year 2006 and newer calling for DEXRON-VI Automatic Transmission Fluid (replaces DEXRON-III and DEXRON-II(E), or recommended for any other vehicle manufacturer that calls for DEXRON-VI, III, or II(E). ACDelco DEXRON-VI Full Synthetic Automatic Transmission Fluid is not for use in CVT (Continuously Variable Transmissions) or DCT (Dual Clutch Transmissions) which require specialized fluids. ? Features & Benefits

Backward compatible with previous DEXRON automatic transmission fluids and can be used as a much-improved replacement for older vehicles/transmissions originally using previous DEXRON fluids

Improved performance over previous DEXRON fluids in: friction durability, viscosity stability, aeration and foam control, and oxidation resistance

Potential to enable improved fuel economy and longer transmission life

Provides for extended drain intervals

Brand Information ACDelco Automatic Transmission Fluids (ATFs) prolong the life of transmission components and provide the protection you need to keep your transmission running smoothly. ACDelco offers a diverse selection of ATFs to fit the needs of various vehicles and transmission types. ACDelco Automatic Transmission Fluid is specifically designed to maximize fluid change intervals and function effectively under a wide range of external conditions

 

ACDELCO TYPE iii(H) ATF

 

10-9240 close

Type III (H) Automatic Transmission Fluid - 1 qt

 

ACDelco ATF Type III (H) is a premium quality automatic transmission fluid for use in a variety of passenger cars and light trucks. It is formulated with select base oils and additives to meet the heavy demands placed on automatic transmissions, including the generation of electronically controlled transmissions. ACDelco ATF Type III (H) is recommended for the following uses: when DEXRON-III(H), DEXRON-III(G), DEXRON-II(E), DEXRON-II, or Type A Fluids are required, in all automatic transmissions built by GM that do not require DEXRON-VI, and can also be used in some hydraulic and compressor systems where excellent low temperature flow ability is required.

Features & Benefits

·         Good frictional characteristics and wear protection provide enhanced cold temperature performance, excellent friction retention, and smooth shifting

·         High oxidation resistance fortifies against rust and corrosion and provides for longer fluid change intervals

·         Wide range of seal compatibility - can be used in an extensive variety of vehicles/transmissions

·         Meets requirements for foam protection and protects against metal-to-metal friction and wear within the transmission

Brand Information ACDelco Automatic Transmission Fluids (ATFs) prolong the life of transmission components and provide the protection you need to keep your transmission running smoothly. ACDelco offers a diverse selection of ATFs to fit the needs of various vehicles and transmission types. ACDelco Automatic Transmission Fluid is specifically designed to maximize fluid change intervals and function effectively under a wide range of external conditions.

 

 

Edited by NTX5467
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As far as the two small barrel hex head plug bolts on the torque converter I do not find a specific torque spec.  But if you look closely at the plug bolt itself the head & long treadless shaft meets with the fine threaded portion without interruption or or step. This would indicate the fine threads allows the plug bolt to seat and bottom out at end of the threading unlike the normal spiral cut on a regular bolt.   I would simply apply a very light coat of thread lock compound made specially for fine threads to keep it in place as the plug bolt itself is designed to be leak proof once set into place and bottoms out.   

 

990012657_DynaflowConverterPlugs-1.thumb.JPG.3fbe3b6d9ac8044972ba584564bbdd5f.JPG

 

 Regarding Type A transmission fluid,  here is a link to a Texas Company that claims to have specifically compounded Type A spec fluid available for sale.  It would be interesting to contact them and interview as to just how specific and correct to original specs there Type A fluid is.  The original used whale oil to what specific qualities whale oil provided that now modern petroleum chemistry can mimic and or improve upon.  

 

https://www.warrenoil.com/site/warren-transmission-fluids/

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12 hours ago, buick man said:

As far as the two small barrel hex head plug bolts on the torque converter I do not find a specific torque spec.  But if you look closely at the plug bolt itself the head & long treadless shaft meets with the fine threaded portion without interruption or or step. This would indicate the fine threads allows the plug bolt to seat and bottom out at end of the threading unlike the normal spiral cut on a regular bolt.   I would simply apply a very light coat of thread lock compound made specially for fine threads to keep it in place as the plug bolt itself is designed to be leak proof once set into place and bottoms out.   

 

990012657_DynaflowConverterPlugs-1.thumb.JPG.3fbe3b6d9ac8044972ba584564bbdd5f.JPG

 

 Regarding Type A transmission fluid,  here is a link to a Texas Company that claims to have specifically compounded Type A spec fluid available for sale.  It would be interesting to contact them and interview as to just how specific and correct to original specs there Type A fluid is.  The original used whale oil to what specific qualities whale oil provided that now modern petroleum chemistry can mimic and or improve upon.  

 

https://www.warrenoil.com/site/warren-transmission-fluids/

My understanding is that they are just a simple pipe plugs, shaped for a special location.  Use sealer on the threads (Permatex aviation or equivalent) never teflon or thread lock.

Warren oil makes some good lubricants, but the type A is not one of them...better choice is their Dex/Merc with a better additive package and leave the type A for the Dollar stores.

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ANY later version of Dexron/Mercon would be friction modified for lock-up torque converters, which I would suspect to be overkill for a DynaFlow.  BUT the much better base stocks and additive package make it a much better fluid for durability and long life.  Plus it's available "everywhere" at decent prices, which is even better.

 

Enjoy!

NTX5467

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