95 Tahoe drivetrain noise

[fast72]

I am having a worsening condition of drivetrain noise under takeoff from a dead stop.Sounds like drums clunking kind of.I thught it may be u joints since it has 110k on it but checked them thoroughly and they are good and tight.Took the drive shaft out and checked the yoke splines and they look good.The odd thing was when I held the rear wheels stationary and turned the pinion it had almost a half inch of slack in it.That seemed excessive to me but I don't know much about rear ends.The small amount of noise can be heard when moving the pinion back and forth.I moved the wheels around to look for obvious bearing wear and there was nothing unusual.Any help would be appreciated in narrowing this down.Thanks