What is the most likely problem with my ?

I have a 93 ford explorer and i have had some transmission problem's. I am a pretty good mechanic and figure its my torque converter. What it does is makes a noise like a clicking/grinding noise in the bell housing area. It also will seen to drive fine then all the sudden will start to stall at stop sighns and act like its locked up and will lug and chatter while i slow down. It shifts fine and goes down the road fine. I dont want to buy a new and find out it was just the torque converter. It has been doing it more and more and now i will not drive it because it does it to much and when it stalles at a light when i put it in drive it acts like its a standard in gear and i am dumping the clutch,no slip involved just locked up.