Q: Transmission noise

So out of no where while driving I pushed on the gas and it started making a really loud zipping noise I guess is how I would explain it...not like the sound of a zipper on a jacket but like umm....idk how to really describe it! However it does it when I push on the gas and accelerate, and it's like it gets louder and faster until it stops then starts again when I decelerate...but not until I slow down almost all the way it's like it starts and stops around the same speeds maybe! But it only does this in drive and reverse...when I put it in neutral it stops so like when I had to drive it to my dad's for him to look at it when I would come to a stop I would just drop it down in neutral so it wouldn't make the noise, but of course when I put it back in drive it starts again...my dad is pretty good with cars and he said he was stumped.. and that he had never heard a car make this noise before so he had a couple of his friends listen to it, and they said it was the torque converter,
My car has an automatic transmission.