zippy,

There are some really good posts on here about this subject. The trans in the 80 81 years were controlled by vacuum they can be very tricky you have to read up on this. The kickdown is nnothing more than a solonoid switch that pulls in when you energize it by flooring the throttle.Try pulling the vac line to the modulator and you should have some hard shifting but dont leave it that way. You can start your troubleshooting with that Im sure there are those who know more than I about this but this is my past experience with one of these trans. More vac softer shift less vac harder shift . good luck