Torque Converter Failed? / broken pieces inside
 

Durring a good burnout / launch I was holding at 7000 rpm for about 5 seconds when this extreamly loud metal screech sound occured then no more forward and only a slight amount of reverse.

Pulled the tranny (th350), brand new 1 day old fluid had that horrible burnt smell and the stall was full of metal shavings and chunks. I think the turbines in the stall failed.

If so what are the chances that the transmission will have to be torn down?
I was hoping to flush it out and get a new stall

You'll need to tear down and clean the trans, and replace the cooler. You won't get all the crap out by flushing. Not even close. Save yourself some aggravation and just do it....

I think something let go in the trans. I have broken a converter in the burnout and had no movement in any gear. Still had to tear the trans down for clean-up. JMO.

sounds like a tear down. also check the sprag to make sure it didn't go out. it will shoot converter full off metal when it goes out.