WELL THE WEEKEND WAS SCHIT TO DO ANYTHING! (RAINY!!!!) SO YESTERDAY IT WAS KINDA NICE, SO I DECIDED TO CHANGE THE RR DIFF FLUID AND CHECK THINGS OUT.THE TEETH LOOKED GOOD W/NO ABNORMAL MARKINGS OR CHIPS. I GRABBED AHOLD OF THE DRUM AND TURNED IT AND THERES ABOUT 3/4"-1" OF PLAY BEFORE THE SPIDERS STARTS TO TURN, AND THERES CONSIDERABLE AMOUNT OF PLAY IN THE DRIVE SHAFT TOO.TO ME ITS SEEMS LIKE I NEED TO REPLACE THE CARRIER.
SO MY Q IS, WHAT DO I NEED TO DO, CHANGE EVERYTHING SINCE IM GONNA GO TO 4.56 OR JUST THE R/P ITSELF?  

Impossible to tell without actually seeing what is going on.  

Hard to tell exactly what it is.  but, I'll tell you this...  i was trying to find the source of a new noise.  In the midst of it all, i found that I had some unwanted backlash.  (kinda similar to what I'm getting from your words) This wasn't the source of the noise.

What I'm getting at is this...  I thought nothing was wrong with my rear dif.  Upon opening it and founding this unwanted backlash accompanied by 'play in the rear drove shaft', I found that one of my carrier bearings where shot.  It's replaced and the backlash/driveline play has been taken care of.  Threads "Rear Diff Noie! Help?!" and "Front Driveshaft Noise! "Help?!"  

unfortunately, my noise isn't fixed yet.  but, I'm getting close!!!

If your Carrier bearings are shot/worn, replace them.  If you plan on dropping a locke do that too while your in there, if finances are there. If you plan on re-gearing fo that to, if finances are there.

If your Carrier bearings are shot, your shouldn't have to worry about reconfiguring shims for backlash so as long as you use what is already there. If you toss in a new gear and different carrier, then you may have to re-shim it.

If the Carrier bearings aren't shot, look into the yoke bearing.  

This is not a end-all be-all answer, but good luck!