Previous Thread
Next Thread
Print Thread
Page 1 of 2 1 2
727 fluid- What to use? #629438
03/03/10 04:36 AM
03/03/10 04:36 AM
Joined: Aug 2003
Posts: 4,481
Mesa, AZ
P
Pat_Whalen Offline OP
super gas
Pat_Whalen  Offline OP
super gas
P

Joined: Aug 2003
Posts: 4,481
Mesa, AZ
I tried a search but it didn't give me too many solid results.

Some people say Type F in a street/strip application. Other's say Type F is too old and doesn't have to additives required to last long.

Some say Dexron is the approved fluid. What I was able to find locally was Dex/Merc.

Transmission is going behind a stock/mild 440 in a heavy Ramcharger. If it makes a difference, I don't want to have to tear down the trans every couple thousand miles and the truck will be driven in Arizona (6 months out of the year might be pushing 100 degrees.)

Thanks in advance.

Cheers,
Pat


Re: 727 fluid- What to use? [Re: Pat_Whalen] #629439
03/03/10 04:43 AM
03/03/10 04:43 AM
Joined: Feb 2007
Posts: 316
Coolville, Ohio
L
Lew Offline
enthusiast
Lew  Offline
enthusiast
L

Joined: Feb 2007
Posts: 316
Coolville, Ohio
I asked this ? not long ago, most of them said type (F), lets see what you stir up. I already put the F in mine.

Re: 727 fluid- What to use? [Re: Pat_Whalen] #629440
03/03/10 04:49 AM
03/03/10 04:49 AM
Joined: Feb 2010
Posts: 18,493
Granite Bay CA
Kern Dog Offline
Striving for excellence
Kern Dog  Offline
Striving for excellence

Joined: Feb 2010
Posts: 18,493
Granite Bay CA
When in doubt, refer to the FSM. The new MOPAR ATF+4 will work fine, but it has detergents that the older transmissions may not need. PLUS it costs more. The Dexron/Mercon is the default replacement for the Dexron, Dexron II and Dexron/Mercon. Mopar Action recommended Type F for better shift quality and less slippage. I've often wondered if it is a problem to switch types on a used trans. It is nearly impossible to fully evacuate the old fluid without total teardown. Would a 95% to 5% mix cause trouble?

Re: 727 fluid- What to use? [Re: Kern Dog] #629441
03/03/10 01:51 PM
03/03/10 01:51 PM
Joined: Dec 2007
Posts: 10,542
BROOK PARK, OH
WILD BILL Offline
Senior Member of the Junior Dragster Club
WILD BILL  Offline
Senior Member of the Junior Dragster Club

Joined: Dec 2007
Posts: 10,542
BROOK PARK, OH
I used Type F for years till I switched to Amsoil in the race car. Still use Type F in the 72.

Re: 727 fluid- What to use? [Re: WILD BILL] #629442
03/03/10 02:21 PM
03/03/10 02:21 PM
Joined: Jul 2008
Posts: 30,424
Florida STAYcation
dOrk ! Offline
The village idiot's idiot
dOrk !  Offline
The village idiot's idiot

Joined: Jul 2008
Posts: 30,424
Florida STAYcation
ANOTHER vote furr Type F .....

And to the guyz that use Mopar4 and AMSOIL .... must be nice to have that COIN to throw-around when it is not necessary !

Re: 727 fluid- What to use? [Re: dOrk !] #629443
03/03/10 02:41 PM
03/03/10 02:41 PM
Joined: Mar 2003
Posts: 15,491
the boonies
aarcuda Offline
I Live Here
aarcuda  Offline
I Live Here

Joined: Mar 2003
Posts: 15,491
the boonies
type F


It's got a cop motor, a 440 cubic inch plant, it's got cop tires, cop suspensions, cop shocks. It's a model made before catalytic converters so it'll run good on regular gas.
Re: 727 fluid- What to use? [Re: aarcuda] #629444
03/03/10 03:15 PM
03/03/10 03:15 PM
Joined: Aug 2003
Posts: 4,481
Mesa, AZ
P
Pat_Whalen Offline OP
super gas
Pat_Whalen  Offline OP
super gas
P

Joined: Aug 2003
Posts: 4,481
Mesa, AZ
So even though this isn't planned as a strip vehicle, type F is still advised? Any rumors to the fact that it doesn't hold up very well to constant high heat?

Re: 727 fluid- What to use? [Re: Pat_Whalen] #629445
03/03/10 03:18 PM
03/03/10 03:18 PM
Joined: Jul 2008
Posts: 30,424
Florida STAYcation
dOrk ! Offline
The village idiot's idiot
dOrk !  Offline
The village idiot's idiot

Joined: Jul 2008
Posts: 30,424
Florida STAYcation
Type F .... holds up BESTER to heat !

Re: 727 fluid- What to use? [Re: dOrk !] #629446
03/03/10 03:49 PM
03/03/10 03:49 PM
Joined: Sep 2005
Posts: 6,516
Santa Cruz, California
L
Lefty Offline
master
Lefty  Offline
master
L

Joined: Sep 2005
Posts: 6,516
Santa Cruz, California

Re: 727 fluid- What to use? [Re: Lefty] #629447
03/03/10 04:13 PM
03/03/10 04:13 PM
Joined: Jan 2003
Posts: 32,930
Grand Prairie,Texas
stumpy Offline
I Win
stumpy  Offline
I Win

Joined: Jan 2003
Posts: 32,930
Grand Prairie,Texas
That ain't cheap compared to type F.

Re: 727 fluid- What to use? [Re: stumpy] #629448
03/03/10 06:02 PM
03/03/10 06:02 PM
Joined: Apr 2008
Posts: 1,285
Pacific NW USA
CompSyn Offline
pro stock
CompSyn  Offline
pro stock

Joined: Apr 2008
Posts: 1,285
Pacific NW USA
Just know there could be possible drawbacks to using Ford Type F in your Chrysler transmission.

Frank Adkins explains in his book, Chrysler Performance Upgrades, that although Type F will cause a Chrysler 727 to shift better, the life span of of the front clutch pack can be dramatically reduced.

Then again in Carl Munroe's book, Torqueflite A-727 Transmission Handbook, "the type of transmission fluid used seems to have a definite effect on clutch life".

Sounds like if you have an all out race car and are not concerned about frequent transmission rebuilds, Type F is the way to go. Otherwise, a good Dexron fluid for a street/strip/show car would be a better choice.


Re: 727 fluid- What to use? [Re: CompSyn] #629449
03/03/10 06:31 PM
03/03/10 06:31 PM
Joined: Nov 2004
Posts: 843
Suffolk,VA
I
ireland383 Offline
super stock
ireland383  Offline
super stock
I

Joined: Nov 2004
Posts: 843
Suffolk,VA
I've always had good results with Dexron III.

Re: 727 fluid- What to use? [Re: CompSyn] #629450
03/03/10 07:56 PM
03/03/10 07:56 PM
Joined: Jan 2003
Posts: 25,796
Rio Linda, CA
John_Kunkel Offline
Too Many Posts
John_Kunkel  Offline
Too Many Posts

Joined: Jan 2003
Posts: 25,796
Rio Linda, CA
Quote:

Frank Adkins explains in his book, Chrysler Performance Upgrades, that although Type F will cause a Chrysler 727 to shift better, the life span of of the front clutch pack can be dramatically reduced.




I would be reluctant to use the word "dramatically" but the simple fact is that type F has less lubricating properties than most other fluids. Consider that the Ford transmissions that type F was originally spec'ed for have clutch packs just like the TF and the friction material is similar if not the same and you don't see an epidemic of clutch failures in them.

Some (myself included) think that the lubrication to the front clutches in the 727 is marginal, a simple mod will take care of that.


The INTERNET, the MISinformation superhighway
Re: 727 fluid- What to use? [Re: CompSyn] #629451
03/03/10 08:58 PM
03/03/10 08:58 PM
Joined: Jul 2008
Posts: 30,424
Florida STAYcation
dOrk ! Offline
The village idiot's idiot
dOrk !  Offline
The village idiot's idiot

Joined: Jul 2008
Posts: 30,424
Florida STAYcation
Quote:

Just know there could be possible drawbacks to using Ford Type F in your Chrysler transmission.

Frank Adkins explains in his book, Chrysler Performance Upgrades, that although Type F will cause a Chrysler 727 to shift better, the life span of of the front clutch pack can be dramatically reduced.

Then again in Carl Munroe's book, Torqueflite A-727 Transmission Handbook, "the type of transmission fluid used seems to have a definite effect on clutch life".

Sounds like if you have an all out race car and are not concerned about frequent transmission rebuilds, Type F is the way to go. Otherwise, a good Dexron fluid for a street/strip/show car would be a better choice.






Hey C S ....

Please define FREQUENT REBUILDS ?

In my 62 .... is a trans that I built back in the middle 70's ... it has had maybe 5 diff motors in front of it and maybe has 40k miles on it. The SAME type F fluid in it since day one.

Manual VB, trick drum, cut-down hemi band .... NO trash in the pan EVER.

Do you BELIEVE everything that you read ?

Re: 727 fluid- What to use? [Re: dOrk !] #629452
03/04/10 12:26 AM
03/04/10 12:26 AM
Joined: Nov 2004
Posts: 7,274
s.w.fl
B
bonefish Offline
master
bonefish  Offline
master
B

Joined: Nov 2004
Posts: 7,274
s.w.fl
in my 11.00 sec b-body street car i just use what ever is on sale or the cheapest,mix and match,been shiftin hard for 35,000 mi.but who knows mabey its gettin ready to prematurly fail.

Last edited by bonefish; 03/04/10 12:28 AM.
Re: 727 fluid- What to use? [Re: bonefish] #629453
03/04/10 12:33 AM
03/04/10 12:33 AM
Joined: Jan 2003
Posts: 27,421
Balt. Md
3
383man Offline
Too Many Posts
383man  Offline
Too Many Posts
3

Joined: Jan 2003
Posts: 27,421
Balt. Md
I have always used the Mopar fluid and I use ATF+4 now. But I have worked for Mopar dealers for the last 24 years so I get the Mopar fluid at a real good price. My brother use ATF in all his race cars also and we have never had any tranny problems. Ron

Re: 727 fluid- What to use? [Re: 383man] #629454
03/04/10 01:51 AM
03/04/10 01:51 AM
Joined: Dec 2003
Posts: 5,314
Carstairs, Alberta, Canada
dave571 Offline
master
dave571  Offline
master

Joined: Dec 2003
Posts: 5,314
Carstairs, Alberta, Canada
If it's a driver, I can't see why you'd want type F. The best in 50's technology can probably be improved on.

Even ford guys stopped using it in 79.

In the same breath, the 727 isn't cutting edge either, so it is pretty forgiving with whatever fluid you want.

For me, I know modern transmissions put MUCH bigger demands on the fluid, as far as heat etc.. That said, modern fluids have to take up the slack.

Much Like 383 man, I work at a dealership (fordstore for me though) and get the fluid for a pretty good deal. I use mercon 3/dexron 3 curently, but we don't sell it anymore. Replaced with mercon 5, so that's what'll be in the car this year.

If money is a factor, a 20 litre/5 gallon pail of dexron 3 is pretty cheap at walmart.

Re: 727 fluid- What to use? [Re: dave571] #629455
03/04/10 09:24 AM
03/04/10 09:24 AM
Joined: Aug 2007
Posts: 601
Mass
C
charge70 Offline
mopar
charge70  Offline
mopar
C

Joined: Aug 2007
Posts: 601
Mass
John K. from the board told me to use a 50/50 mix of Dex/Merc and type F,which is now FA.John.


1970 Dodge Charger R/T S.E. 1969 Dodge Dart GTS 440 M-Code 1970 Dodge Charger 500 383/4-speed w/A.C.
Re: 727 fluid- What to use? [Re: dOrk !] #629456
03/04/10 09:33 AM
03/04/10 09:33 AM
Joined: Apr 2008
Posts: 1,285
Pacific NW USA
CompSyn Offline
pro stock
CompSyn  Offline
pro stock

Joined: Apr 2008
Posts: 1,285
Pacific NW USA
Quote:

Quote:

Just know there could be possible drawbacks to using Ford Type F in your Chrysler transmission.

Frank Adkins explains in his book, Chrysler Performance Upgrades, that although Type F will cause a Chrysler 727 to shift better, the life span of of the front clutch pack can be dramatically reduced.

Then again in Carl Munroe's book, Torqueflite A-727 Transmission Handbook, "the type of transmission fluid used seems to have a definite effect on clutch life".

Sounds like if you have an all out race car and are not concerned about frequent transmission rebuilds, Type F is the way to go. Otherwise, a good Dexron fluid for a street/strip/show car would be a better choice.






Hey C S ....

Please define FREQUENT REBUILDS ?

In my 62 .... is a trans that I built back in the middle 70's ... it has had maybe 5 diff motors in front of it and maybe has 40k miles on it. The SAME type F fluid in it since day one.

Manual VB, trick drum, cut-down hemi band .... NO trash in the pan EVER.

Do you BELIEVE everything that you read ?




Doc, I'm sure glad you're around. Civilized debate is always oh so splendid. Great to see you.

The OP wants to know about automatic transmission fluid options. I informed him of the ideas and opinions of a couple authors, Frank Adkins and Carl H. Munroe, two individuals who are accomplished mechanics and who have been involved in the automotive hobby for decades. Between their statements, it becomes at least somewhat apparent that it's important to select the right ATF for the right application. Don't you think the OP should at least know the possible pros and cons to using any given type of ATF so that he can make an informed discussion of his own?

You provided him information that his transmission may be reliable up to 40,000-miles with Type F and that you feel, “Type F .... holds up BESTER to heat”.

That’s great, maybe he has some directions he can go in now?

I submit to you that since we are not living in the 60s anymore and have had some technological advancements in lubrication technology since then, there very well could be better options than Type F.

Since we know that high performance automatic transmissions can generate lots of heat very quickly and that conventional petroleum products break down and are not very shear stable in high heat extremes, a modern Dexron/Mercon Synthetic ATF may be an attractive option.

And perhaps that by properly building and programming the transmissions shift points, it won’t be necessary to mix and mismatch ATF types to achieve the desired shift performance?

Re: 727 fluid- What to use? [Re: Pat_Whalen] #629457
03/04/10 09:59 AM
03/04/10 09:59 AM
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Mattax Offline
top fuel
Mattax  Offline
top fuel

Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Type F is about the last of the unmodified AFTs.
All of the Dex/Merc and related ATFs are friction modified. The modified ATF's change the way the clutches and bands grab and hold. All things being equal, the clutches and bands will grab quicker and harder with an unmodified ATF than a modified ATF. (They also may effect the release)

Things have become far more complicated in recent years due to the computers for the automatics.
Dexron II or III is hard to find. Here's a repost from another list of my conclusions in 2008 as to
what commonly available fluid to put in a torqueflite 727 or 9xx.

Type F. It's in a category of its own.
The only unmodified atf with a dynamic coefficient that
increases as clutches and bands lock up - resulting in firmer shifts.
If that's what you need, great. Drawback is that the fluid doesn't hold
up as long.

Of the modified ATFs, the options in order of preference:
1. Dexron VI. This is GM's current standard. By definition, Dex VI is
fully synthetic and has the lowest low temperature viscosity. That's
great for street and the first autocross run of the day. However, what
convinced me that this is probably the best current replacement (unless
Type F is wanted) was that several manufacturers specifically list
it as backward compatible to Dex III *and* Dex II.

2. Synthetics. Several manufacturers offer synthetics labled as
appropriate for Dex III applications. e.g. Mobile 1 Synthetic, Castrol
Syntec, Valvoline Synpower. But it seemed that if the manufacturer offered a Dex VI,
they stated Dex VI is the prefered replacement. (Valvoline, Mobile)

3a Dexron/Mercon. These are probably all fine - especially if the trans
has some leaks - since its generally cheaper than options 1 & 2. A lot of
people who post on the web and seem to be knowledgeable like to point out that
Dexron III and earlier 'no longer exist'. What they mean is that
GM is no longer licensing the early versions, therefore what is being sold may
or may not meet the former Dex III standards. My feeling is that may be
technically true, but the companies have other incentives to make sure
these products are what they say they are.

3b Dexron/Mercon - a chronology. Gleanings from the web (which appear to be
more substantial than wild rumors, but you've been warned).
Dexron II 1973 - 1987
Dexron IIe was for electronic controls & had extra cleaning agents.
Mercon 1992- Contained less wax than Dexron
Dexron III c.1993 - Similar to Mercon. Lower low temperature
viscosity than earlier versions. Said to have better oxidation
resistance and improved seal life. Not all agree on the compatibility.

4. ATF+3, ATF+4. Similar to Dexron but formulated specifically for
Chrysler transmission control modules. All of the manufacturer spec
sheets I found on-line seemed to agree - NOT recommended for DEX 3
applications.

5. Mercon V. Seems to be the Ford version of Chrysler's ATF+. Also not
fully backward compatible.

6. Multi purpose: Probably the same as Dex/Merc, but better check the
manufacturers recommendations. Seems like too much of crapshoot for
people who care about how the autogear changer shifts.


These were my conclusions and obviously others may come to different conclusions. I've used Dex II and III, Type F, ATF+, Dex VI at one time or another in my own 727s. The only one that I was really unhappy with how it seemed to effect the shifting were the ATF+3/+4. I'm currently using Dex VI in the leak free trans and Dex/Merc in the Jeep with rear leak.
--
Matt
67 Barracuda nb 340 TF727
85 Grand? Wagoneer AMC 360 TF727 np229

Re: 727 fluid- What to use? [Re: CompSyn] #629458
03/04/10 07:39 PM
03/04/10 07:39 PM
Joined: Jan 2003
Posts: 25,796
Rio Linda, CA
John_Kunkel Offline
Too Many Posts
John_Kunkel  Offline
Too Many Posts

Joined: Jan 2003
Posts: 25,796
Rio Linda, CA
Quote:



I submit to you that since we are not living in the 60s anymore and have had some technological advancements in lubrication technology since then, there very well could be better options than Type F.




Keep in mind that the new generation of fluids are formulated for a new generation of transmissions that, for the most part, have lockup (or partial lockup) converters and overdrive which has the planetary gears running most of the time.

OTOH, the performance 727 rarely used a lockup converter nor does it have the planetaries running the majority of the time.


The INTERNET, the MISinformation superhighway
Re: 727 fluid- What to use? [Re: John_Kunkel] #629459
03/05/10 07:24 AM
03/05/10 07:24 AM
Joined: Apr 2008
Posts: 1,285
Pacific NW USA
CompSyn Offline
pro stock
CompSyn  Offline
pro stock

Joined: Apr 2008
Posts: 1,285
Pacific NW USA
Quote:

Quote:



I submit to you that since we are not living in the 60s anymore and have had some technological advancements in lubrication technology since then, there very well could be better options than Type F.




Keep in mind that the new generation of fluids are formulated for a new generation of transmissions that, for the most part, have lockup (or partial lockup) converters and overdrive which has the planetary gears running most of the time.

OTOH, the performance 727 rarely used a lockup converter nor does it have the planetaries running the majority of the time.




Right, to clarify, I'm not referring to the newest of the new DEXRON® VI, MERCON® LV, SP low viscosity ATFs; don't run those in your 727.

What I am referring to is DEXRON® I, II, III compatible synthetic ATF.

Re: 727 fluid- What to use? [Re: Pat_Whalen] #629460
03/05/10 07:36 AM
03/05/10 07:36 AM
Joined: Dec 2008
Posts: 140
Indiana
J
jef408 Offline
member
jef408  Offline
member
J

Joined: Dec 2008
Posts: 140
Indiana
type f/type f/type f!!!!!!!!

Re: 727 fluid- What to use? [Re: jef408] #629461
03/05/10 08:05 AM
03/05/10 08:05 AM
Joined: Sep 2003
Posts: 1,111
sw michigan
T
TB3CUDA Offline
super stock
TB3CUDA  Offline
super stock
T

Joined: Sep 2003
Posts: 1,111
sw michigan
if type f is the way to go,what maufacturer?valvaline,castrol??or just any type f,also is for race or street use,or both

Last edited by TB3CUDA; 03/05/10 08:16 AM.
Re: 727 fluid- What to use? [Re: TB3CUDA] #629462
03/05/10 09:51 AM
03/05/10 09:51 AM
Joined: Dec 2009
Posts: 580
PA
Moparzrule Offline
mopar
Moparzrule  Offline
mopar

Joined: Dec 2009
Posts: 580
PA


My
Own
Personal
Adrenaline
Rush
Re: 727 fluid- What to use? [Re: CompSyn] #629463
03/05/10 10:20 AM
03/05/10 10:20 AM
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Mattax Offline
top fuel
Mattax  Offline
top fuel

Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Quote:


Right, to clarify, I'm not referring to the newest of the new DEXRON® VI, MERCON® LV, SP low viscosity ATFs; don't run those in your 727.





WRT the Dex VI we'll have to agree to disagree on that one. Your competitors who make Dex VI specifically state it is backward compatible to Dex II and Dex III.

As far as I can tell, the differences in the ATF's friction modifiers are going to effect the way the clutch packs and bands grab. We're talking about what is happening for that brief moment while the clutch is slipping. That timing is critical in an automatic. However, as someone pointed out, it s hardly the only factor. Anyone who has modified their 727 ought to use the fluid characteristics their clutch supplier and/or builder recommends. Anyway, its the friction modifiers that result in Dex VI working fine for a plain ole 727 and ATF+ not working so well.

One advantage the Dex III had over II, and all the newer ATFs have over Dex III is the lower, low viscosity. An analogy to motor oil is that its like having a 10w-40 synthetic instead of a 20w-40 conventional oil. It means that even below operating temperature, the ATF acts more closely to the characterists it has when at operating temperature. For some applications, that's almost irrelevent, others its very important. For short drives and autocross, its important. If you're pulling to the line and loading the torque coverter, the fluid will be at operating temp real quick if it wasn't already.

Re: 727 fluid- What to use? [Re: TB3CUDA] #629464
03/05/10 10:34 AM
03/05/10 10:34 AM
Joined: Dec 2008
Posts: 140
Indiana
J
jef408 Offline
member
jef408  Offline
member
J

Joined: Dec 2008
Posts: 140
Indiana
there is better fluids out there but they are more expensive,theres absolutely nothing wrong with type f.the brand dont matter,its which ever you choose or prefer,ive ran it for years and no problems,especially if you run a stall converter,you would want to change the fluid fairly often anyways.some people claim that it breaks down and ruins the trans!maybe if you only change the fluid every 50,ooo,who does that?

Re: 727 fluid- What to use? [Re: jef408] #629465
03/05/10 12:58 PM
03/05/10 12:58 PM
Joined: Jan 2003
Posts: 32,930
Grand Prairie,Texas
stumpy Offline
I Win
stumpy  Offline
I Win

Joined: Jan 2003
Posts: 32,930
Grand Prairie,Texas
Another vote for type F. Used it for years with no problems.

Re: 727 fluid- What to use? [Re: stumpy] #629466
03/05/10 03:26 PM
03/05/10 03:26 PM
Joined: May 2003
Posts: 15,487
Florida
S
scratchnfotraction Offline
I Live Here
scratchnfotraction  Offline
I Live Here
S

Joined: May 2003
Posts: 15,487
Florida
heres a ? I read on here that hydrolic fluid is even used and mixed with the tranz fluid

whats the opinion on that?

yea or nay..? can it be done safely?I just use the house brand dex/mec or F when I find it

does it matter on the mixing of the 2?

like said you cant get it all out,I just button mine back up with a manual VB..checked and no TC drain plug





Re: 727 fluid- What to use? [Re: scratchnfotraction] #629467
03/05/10 05:47 PM
03/05/10 05:47 PM
Joined: May 2005
Posts: 2,295
dark side of the moon
D
Dougsmopars Offline
top fuel
Dougsmopars  Offline
top fuel
D

Joined: May 2005
Posts: 2,295
dark side of the moon
Type F. Allways used it never had a problem. Local tranny guy here has been building high performence Mopar auto's for over 35 years. Allways recomended Type F. If it ain't broke don't fix it. I'll stick with what has allways worked for me. Type F

Re: 727 fluid- What to use? [Re: Mattax] #629468
03/06/10 09:28 AM
03/06/10 09:28 AM
Joined: Apr 2008
Posts: 1,285
Pacific NW USA
CompSyn Offline
pro stock
CompSyn  Offline
pro stock

Joined: Apr 2008
Posts: 1,285
Pacific NW USA
Quote:

Quote:


Right, to clarify, I'm not referring to the newest of the new DEXRON® VI, MERCON® LV, SP low viscosity ATFs; don't run those in your 727.





WRT the Dex VI we'll have to agree to disagree on that one. Your competitors who make Dex VI specifically state it is backward compatible to Dex II and Dex III.

As far as I can tell, the differences in the ATF's friction modifiers are going to effect the way the clutch packs and bands grab. We're talking about what is happening for that brief moment while the clutch is slipping. That timing is critical in an automatic. However, as someone pointed out, it s hardly the only factor. Anyone who has modified their 727 ought to use the fluid characteristics their clutch supplier and/or builder recommends. Anyway, its the friction modifiers that result in Dex VI working fine for a plain ole 727 and ATF+ not working so well.

One advantage the Dex III had over II, and all the newer ATFs have over Dex III is the lower, low viscosity. An analogy to motor oil is that its like having a 10w-40 synthetic instead of a 20w-40 conventional oil. It means that even below operating temperature, the ATF acts more closely to the characterists it has when at operating temperature. For some applications, that's almost irrelevent, others its very important. For short drives and autocross, its important. If you're pulling to the line and loading the torque coverter, the fluid will be at operating temp real quick if it wasn't already.




It's true, they tell us the latest Dex VI variant is backwards compatible with the Dex's before it. Let's hope their right, remember when they told us that API (SM) rated motor oils were backwards compatible with all other previous API rated oils? Many would disagree with that one today.

One thing is sure, there are some differences in viscosity, for example:

Synthetic Type F: 7.1 @ 212F

Synthetic Dex III: 7.6 @ 212F

Synthetic Dex VI: 6.0 @ 212F

Viscosity of the same ATFs cooled down to 104F

Synthetic Type F: 41.3 @ 104F

Synthetic Dex III: 38.9 @ 104F

Synthetic Dex VI: 29.8 @ 104F

Viscosity of the same ATFs cooled down to 32F (freezing)

Synthetic Type F: 205.3 @ 32F

Synthetic Dex III: 172.1 @ 32F

Synthetic Dex VI: 128.3 @ 32F

Re: 727 fluid- What to use? [Re: CompSyn] #2273406
03/21/17 12:38 AM
03/21/17 12:38 AM
Joined: Mar 2017
Posts: 5
TX
C
CBODY67 Offline
member
CBODY67  Offline
member
C

Joined: Mar 2017
Posts: 5
TX
Not to specifically resurrect this thread, but . . .
Until Chrysler started recommending Dexron (the original) in 1967 or 1968, the prior spec was the "old" Type A, Suffix A atf that everybody used. Ford Type "F" and Dexron appeared in the same model year.

CAR LIFE magazine had an excellent article on the fluids' differences and similarities, all in the quest of "the smoothest shift". The article claimed that in the then-new THM400, GM put more capacity in the clutches so they could make them slip upon initial engagement, which is what Dexron did. Upon initial engagement until clutch "lockup", the rate of slippage was greater, then decreased to "no slip".

Ford went another way. They used less clutch capacity to temporarily over-load the clutch to cause initial slippage until clutch lockup. Their Type "F" fluid had a grabbier initial friction coefficient that made up for the intended slippage in the clutch pack. Therefore, with that initial grabbiness of the fluid characteristics, Type "F" became the defacto "higher performance" fluid at a time when only B&M TrickShift existed as the performance atf alternative. From initial apply to full lockup was of the same time period for both approaches.

In TorqueFlite 727s for 1966, Chrysler went toward the cherished "imperceptible" shift by replacing the "flat" steels (1965 and prior) in the clutch packs with "wavy" steels. That in itself, replacing the wavys with flats, makes for a quicker and firmer shift with normal atf, but unless you know what's what, many might never know it. This was with the old Type A Suffix A fluid.

In the Chrysler "Police Car" book, it mentions that in 1962, the CHP's new maintenance director desired to cut costs, so he bought 20W motor oil and used it in the TorqueFlites as well as in the engines. Only rule was that after an extended pursuit, the unit come in for an oil change of the trans. It was also noted that other brands of transmissions did not take kindly to the 20W motor oil in the automatic transmission.

So, by 1969, Ford was all Type "F" (the incognito "performance" atf), with Dexron in GM and Chrysler automatics. Dexron II addressed atf cooler corrosion issues (trans cooler in the radiator tank), as earlier mentioned Dex II-E was for electronic conrols, and Dex III soon replaced it in the 1980s decade. Dex II-E had a quicker shift than Dex II, by observation, but adding the GM Automatic Trans Conditioner additive (usually for higher mileage units) to Dex II resulted in a similarly faster shift. Dex III came in about the time of more sophisticated lock-up torque converters.

The newer Dex VI is a semi-syn fluid that GM claims is fully backward compatible to all GM transmissions to model year 1949. An Allpar.com article has some great information on the longer service life of the semi-syn OEM atfs. Plus that Chrysler desired backward compatibility, but full-syn had some issues with seals, so semi-syn was used.

In our then-new 1966 Chrysler, upon cold starts, the trans would have a little delay in things getting up to pressure. After the first transmission service, it became necessary to start it in "N", rather than "P", to not have any delays. Allegedly, the factory-fill fluid was a multi-vis fluid, but the replacement was not.

When the LH cars came out, the first atf spec was Dex III + a Chrysler additive. Using just Dex III would result in decreased clutch friction life. The trans controller would monitor for slippage and increase line pressure 100 times/second to combat it. With the friction characteristics of Dex IIi alone, it would hammer the friction material from the facings in the converter and clutch packs. That'w what I read and also confirmed that the fwd UltraDrives were notorious for "running fine" and then wouldn't move after they were parked. The module adjusted line pressure to combat slippage right until it was metal-to-metal in the clutches.

The Chrysler ATF+__ fluids came into being with the UltraDrive and later LH cars. As I recall ATF+3 was backward compatible for earlier automatics.

In later years, many changes to frictional characteristics of atf were made related to converter clutch issues. Some OEMs now modulate "lockup" levels (between 0 and 100%) depending upon operational environments.

GM is not licensing Dex III any more, as Ford is not licensing Type "F" any more, with "Dex/Merc" being the default replacement for Dex III.

Earlier on, it was claimed that if you used Dex in a Ford Type "F" spec transmission, the clutches would cook. Or if you used Type "F" in a GM trans, it would break, but only putting Dex in a Ford Type "F" trans might cause problems. Note that after a particular model year, Ford spec'd Dex for a few years before their "Mercon" fluid family came out. It's suspected that Mercon IV is very similar to Dex III but customized for Ford's desired converter lockup characteristics . . . plus some shops use Mercon IV where Dex III is spec'd

Many trans shops have their own likes and dislikes for trans fluid specs and what they will or will not work in. We've gone from a generic Type A Suffix A fluid spec to very specialized fluid specs over the past 50 years.

Back to the TorqueFlite without lock-up torque converters, historically you can use pretty much any common atf available. Some are a little ligter viscosity than others (faster shifts and better fluid flow), but common Dex III seemed to work just fine. In racing applications, a syn fluid (as Amsoil) works good, too.

The newer fluids have more additives and friction modifiers in them than any prior atf, with some being semi-syn or full syn. As GM claims Dex VI to be backward compatible to 1949, is a semi-syn, that migt be a good choice of "normal" atfs. There are plenty of higher-performance atfs, too. In any event, watch for color and smell changes in whatever atf you use and change it if those things change significantly.

CBODY67


Last edited by CBODY67; 03/21/17 12:55 AM.

66-CL42, 67-CE23, 70-DH43 Each under about 25K built. Numbers decrease with options and colors! How'd I manage that?
Re: 727 fluid- What to use? [Re: CBODY67] #2273804
03/21/17 05:54 PM
03/21/17 05:54 PM
Joined: Jan 2003
Posts: 25,796
Rio Linda, CA
John_Kunkel Offline
Too Many Posts
John_Kunkel  Offline
Too Many Posts

Joined: Jan 2003
Posts: 25,796
Rio Linda, CA
Originally Posted By CBODY67
As GM claims Dex VI to be backward compatible to 1949


Is that reality or simply an excuse to avoid having to have numerous different fluids on the parts shelf? Ditto for Mopar ATF+4.


The INTERNET, the MISinformation superhighway
Re: 727 fluid- What to use? [Re: Pat_Whalen] #2273976
03/21/17 11:03 PM
03/21/17 11:03 PM
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Mattax Offline
top fuel
Mattax  Offline
top fuel

Joined: Feb 2010
Posts: 1,645
Phila. Pa.
CBody67, Nice addition to the thread. Thanks!

Re: 727 fluid- What to use? [Re: Pat_Whalen] #2274092
03/22/17 04:13 AM
03/22/17 04:13 AM
Joined: Nov 2005
Posts: 248
Sweden
T
Tobbe Offline
enthusiast
Tobbe  Offline
enthusiast
T

Joined: Nov 2005
Posts: 248
Sweden
in racing applications more run tractor hydraulic fluid , haven't use it myself.

Page 1 of 2 1 2






Powered by UBB.threads™ PHP Forum Software 7.7.1