Automatic Transmission Torque Converter problems of the 2015 Chevrolet Silverado

Had been complaining since 2 days after purchase that transmission was shaking/shimmying/sputtering. Was pulling onto a county highway off of a residential type road (after picking up granddaughter from school - she was in truck) and truck bogged down & wouldn't go. Intersection is at top of hill and around a corner. Was clear when I started pulling out, but was almost hit by oncoming truck before I got my truck to get on across the intersection. Has been in shop twice to fix it. First time to double transmission flush. That didn't work. Next time a few weeks later, a technician hooked up a computer to my truck so he could manually shift gears while riding with me. He felt the issues and said he saw several problems. Dealership ended up replacing torque converter. Also replaced vlom manifold - whatever that is? that's what it says on work order. The problem still exists. I believe there are bulletins out on this truck's transmission already. I have talked to others who have had the same problem.