Rear diff/driveshaft questions

I have some low speed vibration that I'm trying to figure out. I thought it was maybe the rear wheel bearings, so I jacked up the car to check for play, etc. The bearings don't sound bad and there's no play at the wheels. However I noticed that the wheel will turn about 1" in either direction before the driveshaft turns, and there's a dull clunking sound that is either coming from the driveshaft, or maybe it's coming from the diff and resonating through the driveshaft.

Is this normal?

 

Normal

 

lube the U-joints and drive shaft and see if it improves.