[3.4 grape of wrath]

I've been hunting this vibration/shudder noise coming from the drive line/exhaust area.Transmission is a 4l60e. This problem would occur in second and third gear when accelerating. With my scan tool installed I noticed it would only happen when the torque converter lock up was engaged. After doing some investigating on the internet I found others had the same problem with the 4l60e. The problem was torque converter lock up shudder. The solution comes from a bottle of lubegard platinum transmission additive. I figured I would try the cheap way out first and added the 10oz. bottle to the trans. After two days of driving around problem solved. Time will tell if this is the final solution.