RE: [Chrysler300] Your Car's Tranny Fluids - Synthetic Type F?
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RE: [Chrysler300] Your Car's Tranny Fluids - Synthetic Type F?

There was a long go around on this , on this site, about a year or so ago..won’t rehash. It involves filter pore size  and viscosity of fluid when cold too.  Might look up. Bottom line for me after a lot of wavering around , was mopar atf (?5 or 6) or equivalent , was the best stuff, why 100k miles, with no trans fluid change now. 100% synthetic.  So it flows well at low temp, seemed to be the main upgrade . Tried to find out the why of the F vs Dexron vs mopar atf 5 etc. . What IS different about linings? Are they different ? Inconclusive at best. Linings now vs then? Vague terms like shift quality get into it. I also heard stories that brass parts in some transmissions do not like some additives.


Newer trans filters with finer pores supposedly need the less viscous TF. With older fluids,  and newer 727 filters,  flow may even get choked when cold. Or worse. I did not even know filter porosity had changed.. All this from an SAE publication I happened to read.


It seems the trend is to filter the fluid more aggressively , finer filters, based on 60 years of automatics, which makes sense to me, for long life, and to  be sure it pumps very well at all temps. Thick fluid cold start stresses pumps and seals, pressure goes up.?  . So a return line filter (external ,like 62 300) and the best atf (mopar 4, 5 or 6?) also might make sense.  It is also like 18 $ a quart. Has to be a good reason mopar decided to use that as factory fill?? .


All of this is just 10 W oil , regular , or more expensive , synthetic-- (like Mobil 1) with various additives; hard to believe that auto trans design truly varies in any TRULY significant way , --but maybe they do. All have steels , seals , and friction liners. And all those materials are not the same now,  as in 57. I had NOS cast iron kits, the seals were junk in the bag.


Reminds me how transmissions , manual,  all had to have special high $ “gear oil” in 60’s  ; now they fill with engine oil. (Corvette started that, I think) . Gears are still same gears in there. Bearings too.  Seals are formulated to resist swelling, viton is best. Early transmissions had various things. Seals look a lot different now. Old rubber thick ones get hard.  I also find it hard to believe all these small private label oils can do any real oil refining..right? No way. Relabeling something else. Mobil discovered and researched synthetic out of airplane turbine use, that is the real stuff.. Airplane synthetic turbine oil as a base stock is probably ok in an auto trans.. more than ok.


No strong opinions, just random info…. Your mileage may vary. And an interesting thing --to find out more about it.


Any bad experiences out there? That matters…




From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of Ray Melton rfmelton@xxxxxxx [Chrysler300]
Sent: Monday, May 16, 2016 3:36 PM
To: kboonstra@xxxxxxxxxxxx; chrysler300@xxxxxxxxxxxxxxx
Subject: [Chrysler300] Your Car's Tranny Fluids - Synthetic Type F?


 Hello Keith -
We are ready to install the rebuilt cast-iron Torqueflite in my late father's 1957 Chrysler 300C.  I have purchased (but not yet added) some Valvoline Premium Type F fluid (standard petroleum base).  Although my usage will actually be very gentle and not require a high-performance fluid, I would definitely consider a synthetic fluid IF I could be pretty sure of two things:  First, unless specifically modified, early versions of synthetic fluids (engine oil, transmission fluids, etc.,) often did not contain adequate seal-swelling agents, so they tended to leak, often prodigiously.  Question:  Do you or any of your acquaintances have personal experience with any brand of synthetic Type F fluid, and have their results been leak-free for at least a year?     Second:  Both Royal Purple and Redline offer their synthetic Type F fluids "For Racing Purposes Only"  -- RP even says it is NOT for standard automatic transmissions.  Redline makes a similar admonition, just not quite so specific, so I am loathe to use either of those well-respected names in an application they advise against.   Redline says their fluid has NO friction modifiers in it, whereas I thought "Type F" implied a certain "package" of friction modifiers, so I don't know what to make of their statements.  The Redline advisors say they have no advice to offer regarding my proposed use, and hence would not recommend their product without specific experience.  However, ALL the synthetic manufacturers talk about greatly improved wear characteristics, extended service life, etc.   
I see that ATI (makers of some extreme high-performance transmissions and torque converters, etc.) offers a full-synthetic Type F fluid (available through Summit, JEGS, Amazon, etc.)  They say it is for "Racing, street rod and high-performance applications".   Their tech rep could only say that they developed the fluid for Joe Gibbs Racing, and they've had excellent results in dragsters and Funny Cars, with no reports of undue leakage or other performance or compatibility issues.   I would like to give that stuff a try, especially if anyone in the Club has favorable experience with it.  Or alternatively, I would like to hear any reports of unfavorable experience with ANY of the full-synthetic Type F fluids.  It's not prohibitively expensive, either, at $98 + shipping for 12 quarts from Amazon.


If I don't hear any adverse comments, I may just go ahead and be the first "guinea pig"!


Ray Melton

Las Cruces, NM

1957 300C convertible  (almost ready to roll, again!)

To: finsruskw@xxxxxxxxxxxxxxx
CC: agmoon@xxxxxxxxx; chrysler300@xxxxxxxxxxxxxxx
From: Chrysler300-noreply@xxxxxxxxxxxxxxx
Date: Sun, 15 May 2016 14:06:59 -0400
Subject: Re: [Chrysler300] You Cars Tranny Fluids


A few years ago there was a pretty lengthy thread on our forum about which ATFs were both suitable and available for our Torqueflites. The original ATF in the cast iron Torqueflite was Type A, but that is no longer being made and offered on the market. It has been conclusively agreed that Type F works very well as a substitute for Type A, and furthermore that most other ATFs, like Dexron and Mercon, will induce disappointing (and sometimes strange) performance characteristics.


ATF is the fluid with the very most critical specifications of any in your car. Getting it wrong can mess up the transmission functions, and even wear it out prematurely. So yes, Go with only Type F in your Torqueflite. 


And your question about synthetic vs. petroleum base? You're probably not going to stress your ATF by racing or pulling a trailer anymore, but it is true that synthetic is superior to petroleum-based in many performance characteristics, and inferior in none. So you'll probably be fine using standard Type F, and you'd be finer yet using Redline  or Royal Purple synthetic Type F. 


Keith Boonstra


On Sun, May 15, 2016 at 12:16 PM, 'David Schwandt' finsruskw@xxxxxxxxxxxxxxx [Chrysler300] <Chrysler300-noreply@xxxxxxxxxxxxxxx> wrote:


I have no trouble finding type F at WalMart

So, why mix them at all?

While I had the drivetrain out a couple years ago, I changed the oil in the
trans and the T/C and went with type F

Noticed better shifting right away.

From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On
Behalf Of 'Allan' agmoon@xxxxxxxxx [Chrysler300]
Sent: Sunday, May 15, 2016 11:12 AM
To: 300 Club Listserver
Subject: [Chrysler300] You Cars Tranny Fluids

Hi all,

Don't know if this thread has already been done or not don't see anything
so... If these answers are there we apologize, please send us the archived
location(s). Thanks.

1. Is it correct that type F and Dextron are pretty much the same tranny
fluid except the Type F has a slightly higher friction coefficient? There
is no problem with mixing them?

2. We can use any of todays tranny fluids that replace dextron and or
Mercon where either was called for in the original owners manual.? We
happen to have an F with cast iron torqueflite.

3. But what about synthetics vs. Dino tranny fluids? Should one use 100%
synthetics? Can you mix them with Dino. oil too?

4. Also today's tranny fluids, for example Valvoline Dex/Merc lists use in
certain Fords, GM and foreign cars but doesn't list Chrysler as a use for it
but they mean the newer Chryslers right?

Have a few old quarts of leftover type F from somewhere and will use them
over time to keep topping off the F's tranny if I can use them for this.

Thanks in advance for any responses. We appreciate your time and thoughts.


[Non-text portions of this message have been removed]




Posted by: "John Grady" <jkg@xxxxxxxxxxxxxxxxx>

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