Synthetic vs non synthetic ATF

[Imperial dude]

Ok, I've got a 1964 Imperial, pushbutton automatic that has a pan gasket leak
I've hunted high and low for +3-4 ATF that's non synthetic and am having no luck
Is it ok to put synthetic fluid in it? Or should I keep searching?
The trans was rebuilt in 2011 if that makes any difference
Any leads on where I might find non synthetic? I've tried autozone, advance, NAPA, O'Reilly and even Wal Mart with no luck

 

[detmatt]

Synthetic should be fine.

 

[CBODY67]

Seems like the Chrysler +3 spec is semi-syn, with +4 being full syn?

Dexron-spec atf is available as "Dex/Merc" in Valvoline and other brands. Just bought 2 gallons of Valvoline Dex/Merc at the local WalMart for about $14.00/gallon. Dexron became Chrysler's pre-1995 atf spec, from about 1968 onward, replacing the old Type A Suffix A spec.

Your judgment call,
CBODY67

 

[Slap Stick]

ATF +4 is backwards compatible with ATF +3 and Dexron. Its whatchoo want.
DO NOT USE UNIVERSAL FLUID!
My 92 Dakota A518 states on the stipdick use ATF +3. Whatever was in it when I bought it started foaming while on a trip so I stopped at the first place I saw, a Chrysler dealer. They changed the fluid with ATF +4.

 

[bronze turbine]

I think what you want is the fluid labeled "Dexron/Mercon". I've heard ATF +4 works great in a torqueflite but is not compatible with the old Dexron III type oil and shouldn't be mixed. You won't find non-synthetic ATF +4, it's synthetic by specification.

 

[CBODY67]

Remember, the OP's vehicle is a '64 Imperial, for which the OEM-spec fluid was "Type A, Suffix A" atf. Which was replaced by Dexron-family fluids in 1968. Which are now usually listed as "Dexron/Mercon" non-syn atfs.

The "+3" atf and the later "+4" atf had friction modifier/oil basestock upgrades to deal with things like lock-up torque converters and modulation thereof, plus cinputer-controlled line pressures in the UltraDrive fwd transaxles of the 1980s-1990s. Which, respectfully, weren't around in 1964 or 1968, fwiw.

Now, obviously, the current +3 and +4 Chrysler atfs are much better "oils" than even the later Dexron III fluid, as far as that goes. Just as the full-syn Dexron VI is a better fluid than non-syn Dexron III. Dex VI is backward compatible for ALL Dexron-family and prior GM atfs back to 1949.

Just as in the prior spark plug threads of "what to use", a personal cost-benefit consideration might be in order? Plus knowing what the particular OEM-spec atf was for the vehicle when produced . . . and what it might have superceded to in later years.

Just some thoughts,
CBODY67

 

[mrfury68]

You want the Dex/Merc type ATF. Also get a rubber coated steel gasket & make sure the bolt holes in your pan aren’t “dimpled” inward. You can check your pan’s bolt flange with a straight edge to be sure. I did mine this past spring and I have no more leaking pan. Those old cork gaskets tend to wick up fluid as they age and then start to leak, especially if the car isn’t driven a lot. Good luck.