Alan Pritchard

I was on my way home Thursday and my truck was doing fine i got up to speed and the trans just let go like i was in neutral, I slowed down and gave it fuel real slow and drove fine for about three miles and it did the same thing but this morning no problem, I also feel a little vibration, I dropped it off at a shop and was wondering if that's what the torque converter will cause and if so should i up grade it?