back of tranny(passenger side) right above the pan. I believe there is screw-in & plug-in types. When mine went south, I unplugged the vacuum line from the carb and the smoke stopped. *Start the car and pull the line from the carb, see if the smoke goes away. (Mine did almost instantly) When it, modulator valve, goes bad it puts tranny fluid in the carb, which then burns out in a beautiful cloud of white smoke.
I guess I must start by asking: this is a C4 tranny right If so, all I did was find the line coming out of the modulator valve, trace it up to the carb. Then start the car and pull that line off the carb, with the car running. If the smoke goes away, its the modulator valve; if it doesn't, then its something else
O, you did not mention you had the 4 tire model....that opens up another batch of senario's I am not a tranny guy....just sharing my experience that I had with a similar problem.
I guess I should have ask: 1) is it running? 2) if so, is it running normal aside from the smoke? 3) is it running hot?