"Clunk"

K I have not looked at crank shaft well be looking at that soon. Also plan on taking a look at cv joints. That same day I was planing on doing a once over on the trans and flex plate lucky for me she is not my daily driver. The vibration starts when I hit haighway speeds I didn't even notice until a buddy of my pointed it out to me. So I honestly think the cv joints are going and that is causing the vibration and to get to flex plate I have to drop the rear end anyway so I figured do it all at once. Let me know if this also a bad idea.

Does it vibrate in Neutral? If so, it's not the CV joint.

You can isolate the engine from the drive train by disconnecting at the front flex plate.

I haven't done it, but I believe you can do the same at the rear flex plate by disconnecting it from the torque converter. That should tell you whether it's the torque tube or not - assuming it's still there after the front flex plate is reconnected.