Mystery stalling when put into drive?

I was on my way home from work several months ago now. My car stalled on me at a relight started back up just fine but when put into gear it shut off immediately as if I was turning my engine off. Please, please help I was told it was torque converter locked up. I did a swap with entirely different trans and still same thing happens seems as if it's only when the break is applied. Someone please help before I junk my car. Thanks