I can't find Dexron II or Mercon II.   What is an ok substitute for the 55 Tbird Fordomatic.  As usual, thank you.

Mercon is now Mercon V.  Others may chime in but I have always used type F in Fordomatic and Cruiseomatic transmissions with never an issue. I always purchase the Motorcraft branded fluid to insure excellent quality.


64F100 57FAIRLANE500

Dexron 2  and Dexron 3 are now Dexron VI

  

F is available, Castro’s lists it. Valvoline has a compatibility list that shows 2 Dex/Merc and Type F for 1980 and earlier Fords.
Both brands listed on Amazon, last time I was in Pep Boys they had both F and Dex/Merc.

56 Vic, B'Ville 200 MPH Club Member, So Cal.

What is the best substitute for the now defunct Type A in our Fordomatics? Thanks.

Type "F",   for transmissions manufactured in the 70's and earlier as per Motorcraft description. It's NOT expensive. NPD offers it for a reasonable price or the Ford store.   I've used it in Fordomatics & Cruiseoatics for decades without any issues no mater when or where I sourced parts. Hope this helps, JEFF..........


64F100 57FAIRLANE500

If you read the technical section of the CTCI restoration manual for 1955-57 Thunderbirds, it does not recommend Type F. Type F replaced Type A, which caused premature failure of transmissions, due to slippage desired for smooth shifts. Type F reduced slippage and firmed up shifts. For that reason, Type F is used by some drag racers and is recommended by some torque converter manufacturers. However, Type F requires more frequent fluid changes and will not extend the life of the transmission, as will Dexron replacement fluids. 

Even tho I responded to the original question. I have a 1962 medium case Cruise-O-Matic behind the 292 in my 56 Victoria. The shop that did the work installed Dextron ll and recommended it. As I have removed the pan and made leak repairs (were not necessarily because the problem was a vent hole) I use what was compatible by reading the backs of ATF qt bottles. I have not had any shift or problems I can feel. Maybe it’s wrong but I buy the auto parts brand usually O Reilly’s as they are the closest. It doe not have a specific labeling number. Compatibility is on the back of the container.

56 Vic, B'Ville 200 MPH Club Member, So Cal.

I'm NO expert on Auto trans, I have only owned one in my lifetime. From what a guy I know who has been building them all his life told me that Ford went from type A to F when the friction materials changed. So depending on your trans having original material or it has been rebuilt using new materials that determines what fluid to use..

trans expert at ford dealer told me merton is great. used it on a older recedes ,stoped the sloping shifts, asked hime about ford automatics, he claims works great as he had a 57ford auto ??