Blown Torque Converter seal

[petticd]

Hi, recently bought a 1968 240 with a BorgWarner 35 Auto transmission and a leaking seal. After replacing the seal the gearbox failed to change up, this we diagnosed to a problem with the kickdown cable failing to return. We run the car without the cable connected and it changed through all gears, but very quickly. The cable has now been fixed and upon test drive yesterday we only got gearshift between 1-2, however, after about 20 minutes of driving, it looks like the front seal (converter seal) has gone again. Fortunately, this happened while holding the car in gear outside the house while waiting to reverse up the drive.

Would having the kick down cable incorrectly adjusted have caused premature failure of the seal?
If the above was at fault, when correctly adjusted do we need to replace the seal again or will it be ok with correct pressure restored in the box?

Anyone got any suggestions?

Regards