Loose Rearend

A while back i wrote about a clunk in rearend on takeoff.Ive noticed something different my rear axle seems to be loose. For instance when i was tightening my yoke nut after changing seal i noticed when cranking ti tighten the whole rear axle would kinda twist. Its not like all over just when a real load on it. Tonight i noticed driving along sometimes it feels like ive got no shocks and hitting bumps in road the truck is up down up down. Shocks are good was wondering if something back there could be loose causing this and when i takeoff the clunk in the rearend could actually be axle moving. THANKS DAVE

trying to track anything loose when pushing up and down on driveshaft there is play at around transmission mount. Im sure there should be some but i can with one hand push up and down a good quarter inch.Is this normal. One more thing where the shaft goes into the rubber of the seal on back of tranny you can see almost a quarter inch of a clean spot meaning where it turns the rubber cleans shaft. Why is it clean out there this means something is sliding back and forth dont know what to do next.