So here's what I got going on. I got a 1982 bronco 302 with a c6 I have no forward gears with the modulator valve hooked up has reverse with and without the valve. If I unhook the vacuum line I can get it to creep forward and eventually it goes with no problem haven't tried to go over 15-20 mph so not sure it shifts. Truck sat for a number of years before I got it I have changed the fluids currently doesn't have the kick down linkage hooked up trying to get it to work with new carb

 

The internal seals are old and hard. They need to be replaced. It's rebuild time.