Nothing is going to fix the shudder issue but a torque converter! I would have lost it on the dealership if I was you. It's simple, the bulletin explains it very clearly, many converters have been replaced due to this problem and I have yet to hear that it didn't fix the shudder. My dealership was doing 3 others the same week they replaced mine. It's not rocket science. Replace converter... Problem solved. They sound like a bunch of loons. I would definitely take it to another dealership.