What is the best trans fluid these days for an A-727

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jerry6

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That is driven only in summer , mostly street with 2 or 3 days at the track . Not interested in hardest shift , but longest life , cost of fluid is not a factor , as a rebuild is always 20 times the cost of the most expensive fluid , cheap insurance .
And I read the other threads, seems no consensus , but there were different needs in that thread , ie hard shift , best ET ,this is for long life street driving .
Are syn fluids recommended for a 727 ?

Thanks
 
I had asked a few mopar trans mechanics and most were telling me that Wolfs Head Non syn.type 3 seems to be what most recommended. That was for use in a 69 727 BB trans that I had rebuilt.
 
Me, I like to base my decisions about these kinds of matters on facts that come from proper, rigourous, scientific tests, not marketeering talking-points that come from "dealers" of particular brands of overpriced oils and fluids. The (objectively) best Torqueflite-compatible trans fluid on the market until recently was Chrysler Mopar ATF+4. It is misunderstood by some to be "too slippery". In fact, ATF+4 is a significantly better fluid in every way than Dexron -II, -III, or -IV and ATF+ (+2, +3), and it does not cause, promote, or aggravate slippage. It maintains the specified viscosity across a temperature range that's wider at both the hot and cold ends, its lubrication and antiwear properties are better, it's more resistant to oxidation, sludging and varnish formation, and it smells better. It might even taste better, I don't know. There's an extremely detailed Chrysler Engineering paper comparing every aspect (except taste) of ATF+4 vs. ATF+3, ATF+2, ATF+, and Dexron-III/IV.

Then along came GM's Dexron-VI, which is another extremely high performance fluid (where "performance" refers to all the things a trans fluid has to do...lubricate both metal-and-metal and metal-on-friction without screwing up the frictional elements' ability to grab and keep hold of the metal, remain stable when cold and when hot, resist foaming, etc).

The RWD Torqueflites really don't need anything more exotic than a good-quality ordinary Dexron (present spec is the newest Dexron VI, though you might still find some older or off-brand Dexron IIIe or other previous Dexrons on the market). I do run ATF+4 in mine, and they all seem happy with it. But the main point here is you really don't need to sweat it. You don't need to spend unnecessary money on exotic-brand fluids or special "race" fluid.

(And because someone's likely to bring it up if this fluid discussion takes hold, Type-F is an archaic fluid with seriously inferior performance by just about every measure. Torqueflites will hold up fine with Type-F, which is mostly an illustration of how rugged the Torqueflite is.)
 
i have used syn fluids in all my cars for over 30 years and have never had a failure , except one 1998 explorer trans go at 250,00 km .First thing I do with my new cars is change all the fluids for syn fluids ,
So if I put CHY atf+4 it will be a good choice ? I believe in synthetics , just not sure on a 1970 transmission , but if you say it will not do damage , it's a go
 
my 74 dart se 318, 904 tranny drinks atf+ 4 only. and as i have been dealing with a leaking problem at the pan gasket and have gone through gallons of the stuff over the last 8 months It must be good stuff. store brand is fine as most of the stuff is made in the same plants.
 
I was just told by a very respected tranny builder(Harry Manovich of Milton transmission)that the ATF-4 is hard on seals and bearings over the long term.He recommended Dextron III for my 904.Too each his own I guess?:-D
 
I'll ask my transmission guy , he's been in business for 35 years , but can't imagiine how syn fluid would be hard on seals , they said the same about syn motor oil back in the day , and i have never had a seal leak on very high mileage cars . My last 4 cars had over 450,00 km with no leaks . Just not sure about such an old cars though .
Same old trouble who to believe , engineers that design and spec things or the guys that repair build , always hate these arguments .
 
Not trying to argue,this is why I put..to each his own..I had the ATF4 in my tranny at first,then when I had issues with a cracked casing and swapped internals to another case, I had asked him which is best?This is when he mentioned about the long term problems.I guess it,s all in prefference for your application,which mine is for racing.
 
Thanks pettybludart , not trying to be difficult , always the same when it come to syn vs dino fluids . Are you still having the seal leak on the trans ? Is the syn fluid the reason given for the leak ? I had 2 rebuilds leak from 1 front and one rear seal ,but they were using dino fluid . I grenaded a few 904's in my day , yours looks worse than any I blew up .
Is your trans guy saying the syn fluid was a contributing factor ? With the price of a rebuild don't want to be putting the wrong fluid in , so trying to get as many opinions as possible .
 
My leaking issues were do to a bent driveshaft(when I tore the spring perches off at launch)My builder is also putting a dial indicator on to lineup the housing/engine.Hope my tranny issues will be solved?Of course it,s nearing the end of the season,but still have 2 events left for my nostalgia club.
 
slantsixdan said:
Nope. He's either makin' it up or he's misinterpreting what he thinks he's seeing.
Click to expand...

That has been the argument by most mechanics for years now , of course the engineers that design the stuff and run rigorous test , not just anecdotal evidence get my vote . But I will still ask my transmission guy what he thinks , he's been building bullet proof trans for me for 35 years and usually goes with good scientific data . He tends to side with rigorous large sample tests .
 
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