Everything he said is ok, the transmission is not broken and must only be adjusted. He checked vacuum, linkage, modulator and so on. I checked our area for transmission specialists nearly all i contacted are not able and have no experience with that kind of transmissions.They can do the modern electronic controlled 7/8 gears transmissions.īut I found one company where an older guy works that nows something about. I adjusted the modulator with no effects.Īfter that i tried to find professional help. I changed the modulator but the problem was steady. I checked for vacuum problems with a vacuum gouge and everything was correct. Mine is shifting precisely at 43mph and then with a kick. While checking with the manuel i found out that shifting from 2nd to 3rd ist to late. In the winter i did not work on it because driving on wet and salty roads it is not good for the car. Maybe you can even get the gauge into the passenger compartment and take it for a spin on the Autobahn!
![1963 ford thunderbird venting controls 1963 ford thunderbird venting controls](https://live.staticflickr.com/3617/4559790819_fa958589a6_z.jpg)
So I would hook up a pressure gauge to the transmission and do the stall tests. throttle is wide open.) I believe some transmissions inhibit shifting into reverse when manifold pressure is low to prevent transmission damage but I don't know if Ford did this. As far as I know, Ford vacuum modulators vent control pressure when manifold pressure drops (e.g. And that vacuum modulator can be a problem too. There are control pressure tubes in the transmission that can have small cracks that can vent pressure for example. So any lack of control pressure can cause a harsh downshift.
![1963 ford thunderbird venting controls 1963 ford thunderbird venting controls](https://www.beverlyhillscarclub.com/galleria_images/13746/13746_p40_l.jpg)
To offset that, the throttle control valve vents control pressure depending on how far down the throttle pedal is.
![1963 ford thunderbird venting controls 1963 ford thunderbird venting controls](https://ccn-journal-prod.azurewebsites.net/media/2022/06/26567275-1963-ford-thunderbird-std.jpg)
When road speed and pressure increases more, it works on the smaller surface area to pop the 2-3 control valve and shifts again. There are two control valves (1-2 shift and 2-3 shift.) The 1-2 shift control valve has a larger surface area or weaker spring, so when road speed pressure increases, it "pops" first, shifting up. A road speed governor/oil pump increases control pressure as road speed increases. Is it fixed Wolfgang? If so, can you share what the problem was? If not, have you checked the operating pressures?