No vacuum modulation on 700R4. Uses throttle valve to control pressure through cable. I would look into the backfire issue you are experiencing. There also is a downshift valve that may be sticking or spring broken.

 

not that I can find.. I hooked up all my vacuum lines when I replaced the distributor. It fixed my 4x4 and a.c. and my cruise control but not this issue. I've got to be missing something

 

See Transman's advice. It's sound if all other things are up. Addressing the engine issues may also solve the transmission problem.

 

thank you both. Im just home from work and getting on it now. Fingers crossed