Apologies on not chiming in earlier. The transmission is closed up and ready to fill. I went ahead and pulled the pinion carrier out to address a very bad leak while the car is on stands. Have all the parts, just need to get preload fine tuned and back together. 

Didn't want to fill the trans and test and then have to drop the driveshaft when doing pinion seal later and loose some ATF. Car needs quite a few other things, but trying to not go overboard with doing too much at once... famous last words.




Will be sure to update y'all when I get it back on the ground. Thanks again for everyone's help and advice!

Kent — Round Rock, TX
'56 F-100  | '56 Crown Vic  |  '57 Fairlaine 500  |  '57 Thunderbird

Update — Success!

Just got back from test driving the 'bird. It's like driving a different car now. Everything behaves like it should. Talk about a relief!

Did the pressure test before taking it off the stands (as several of you mentioned) and had to lengthen the rod several turns to get the pressure up to specs. If you baby it down the street, it'll shift about 19 mph. If you drive lightly down a residential street, about 22-23 mph. All relative on throttle pressure — just like the book says. Feels like it's about where it needs to be.

The accelerator is so much lighter feeling and easier to hold. Before it was fatiguing after a while cruising down the highway (due to binding).

Wanted to thank everyone who answered on this thread and shared their knowledge. It is GREATLY appreciated. Special shoutout to FORD DEARBORN who spent a lot of time walking me through the troubleshooting process and nailing the issue. Everything I've learned during this fiasco is going in the vault and should hopefully help me or someone else in the future. This is a great site and the level of knowledge and helpfulness is very humbling. Thanks again for helping get this old 'bird back on the road!



Kent — Round Rock, TX
'56 F-100  | '56 Crown Vic  |  '57 Fairlaine 500  |  '57 Thunderbird

Good the hear you got it sorted out. So now You know it was the Transmission Shop that caused the Problem. The Manual is very useful if You take the Time to read it. I had to replace the shifter Arm Seal on mine which involves  dropping the Valve Body. Used the Book instead of paying a Shop to do it. It is important that the Accelerator Linkage and  the Throttle Pressure Rod be properly adjusted as You have shown with Yours.

  

Kent, I must have overlooked it, but what transmission fluid did you end up using?

Type F. I know this is a highly debated subject. We've always run Type F in all our fordomatics and never had any issues. Shifts firm but not harsh. Very positive feeling. Downshifts are no longer noticeable unless you specifically feel for them.

Kent — Round Rock, TX
'56 F-100  | '56 Crown Vic  |  '57 Fairlaine 500  |  '57 Thunderbird

I agree! Had to read it several times as it gets very technical, but explains everything very well. Much better source material than what is printed now days. 

Glad you were able to get yours sealed up and avoid the shop. Anything to keep it out of the shop is a good thing!

Kent — Round Rock, TX
'56 F-100  | '56 Crown Vic  |  '57 Fairlaine 500  |  '57 Thunderbird

I found most shops cause problems on these year model fords.  My '56 was taken to a shop and the last time it went before sitting was the late 70s early 80s.  Im not kidding they didnt even block up the bell crank with the 1/4" drillbit like the shop manual says to keep the bell crank in specified position before making the carburetor rod adjustment.  Mine was so out of adjustment I had to adjust not just the bell crank, but replace the carb linkage as well as they cut it off to make it work and I also had to adjust the rod to the transmission as it was out of adjustment as well.

1956 Ford Fairlane Town Sedan - 292 Y8 - Ford-O-Matic - 155,000 mi