Rear end Gear noise...what is the cause

[Petersubaru]

I hear or at least I think the noise is coming from within the rear end gear housing ...in gear or in neutral when coasting the noise is the same...a flopping sound..I have heard this sound before in more extremly driven cars... the '86 loyale has only 250K miles mostly highway driven, with the rear end oil changed regularly,... it seems a bit early for problems in this area....when slightly turning the drive shaft in either direction, I notice that the CV axles on both sides of the "pumpkin" seem to go more up or down first before beginning to rotate...would this be normal because of the short splined stubs coming out of the "pumpkin" with a sloppy fit for the cv axle to fit on...or just maybe, is it the bearings within that are showing signs of excessive wear??