With the original Fordomatic, if you place it in Dr, and then pull off under normal driving conditions (in other words, don't "tromp" it lol), you should only have ONE shift from second to third. That is the way to tell very quickly whether or not you are really in 3rd gear. Starting in Lo, and then shifting to Dr will take you from 1st and then to 2nd. Leaving the car in drive and continuing to accelerate will eventually put you in 3rd gear.

I know we have been all over the place here, but all of the tire calculations are not worth a hill of beans unless you have shifted into 3rd gear. The original Fordomatics took OFF IN SECOND GEAR from a stop and in the Dr position on the selector.I believe you are in 3rd gear at 3000 rpm at 55 mph. Have you had a shift when take off in Dr? If you have then YOU ARE IN 3RD GEAR, if not then you ARE ONLY IN SECOND.

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

I have not felt a shift and the tack never drops off at all you would think that there would be a little fluctuation of the shift right ?

I still think I'm am not getting a shift

  (  I have not felt a shift and the tack never drops off at all you would think that there would be a little fluctuation of the shift right ?                 Try this. Start in manual low. Shifter in L. Speed up to 15 MPH and read the tach. It should be higher than idle RPM. What do you see? TELL US WHAT YOU SEE. Then let off the gas. Do you have engine braking, yes or no? TELL US.Now start in L and at 15/20 MPH shift to D. Read the tach before and after the shift. TELL US (RPMs)It is possible that the governor is stuck at full open and oil pressure is preventing your FOM from going into second gear. This is not very likely but it is possible. What is also unlikely is that you can go 55MPH in second gear at 3000 RPM. So check your equipment and your numbers. Pete  

My take - you are NOT shifting from 2nd to 3rd at all

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

One thing to bear in mind:The speedometers in mid-50s Fords are notoriously inaccurate.An indicated 55 may only be 47-50 MPH.If that's the case,you are staying in second gear.

 

Paul,

Boonville,MO

I had my gps hooked up that's how I got the 55 mph.

I agree but how do I fix that.

Pete
Hers what I got at 15 in L it reads 1200 rpms
At 15 to 20 put in drive felt the shift 1100 rpms
Is eng drag when you leave off gas.
Will cheep tires on a down shift to. L
Put it just keeps going up with no shift to 3000 at 55

It sounds like you have pretty good evidence that the 2-3 shift is not taking place. To determine the cause of the transmission problem is pretty difficult and likely not something you can easily do with the transmission in the car. The following text comes from a 56-57 Fordomatic manual:

The shift from the intermediate to the high ratio is accomplished when the front servo (operating the front band) is released and the rear clutch is applied. This is accomplished by directing governor pressure to the face of the 2-3 shift valve and to the governor plug. As the shift valve moves inward, passages are uncovered to direct control pressure to the release side of the front servo and to the rear clutch. When both clutches are applied, the primary and secondary sun gears are locked to the turbine shaft to provide the high ratio of 1:1.

All of that means that there are several possibilities for a "no shift" condition. The governor could be sticking and not moving as the centrifugal speed increases. The rear servo and or rear clutch could be inoperative or the front servo, front band could be sticking closed. There is a procedure in the manual to remove the governor while the transmission is in the car, but beyond that, it sounds like a transmission overhaul might be in order at some point.

Good luck,
Dave