Rear Axle or Gear Confusion

Hey FABO, sorry this is not specifically for an A Body but it's MOPAR nonetheless.

1975 Trailduster, 3.55 suregrip, 2WD.

I had the rear end off the ground working on the brakes. When I put the wheels back on, I noticed that I can move (turn) the wheels about 1/4" before the driveshaft yoke starts spinning. I can hear and feel it when the yoke starts to turn, it has a little bump then it starts moving. I can see directly through the wheel well to the yoke, so I can see exactly when it starts to turn.

Is this a symptom of bad bearings or something in the ring gear, or something else all together? Or, is that normal?

Thanks for any replies.