SRT 2005 64,000 Miles

SO, I've been chasing this issue for a long time now, basically there is a HUGE clunk/Bang feeling when the car goes anywhere from Park to Reverse, Drive to reverse, or Neutral to Reverse. (can slightly feel it when put into Drive)
I mean you can really feel it. Feels like someone Rear ends you every time you put the thing into reverse and everyone comments on it anytime they are in my car.

This problem has been always present since I bought the car a little over a year ago but now it seems like it is getting worse.

It also occurs if I Press the throttle hard then immediately let go. Or sometimes form decelerating off of high speed in a higher gear.

I have checked these forums very thoroughly and can't seem to find a problem related directly to mine.

What I have checked so far.
1.Trans Mount - Good, Replaced anyways... No fix
2. Both ends of the driveshaft Flex discs - Fine
3. Couldn't easily see the center support bearing, but don't see that causing this issue.

Grabbing the Driveshaft and moving it back and forth, it moves about 1/2 - 1" I'd guess and I can sort of replicate the sound by doing this. It sounds like it's coming from the trans itself.

Unsure how much free play is allowed in the driveshaft

Could be coming from the Diff? But usually if the ring gear an pinion are misaligned you have other problems I would think like whirring sound form the diff.

I don't have a lift so trying to look at everything under the car is PITA...

If anyone knows of anything else I should be checking I would greatly appreciate it. I dont want to actually break something important!!!

Also car drives totally fine otherwise

Thanks for your guys support!
-Darren