Posi Question

Hi guys, quick question. Have a 8.75 with 3:91. I got the posi about 2 years ago from a shop that was bench tested however lately I noticed that when the rear is up off the ground and one wheel held tight the other will move about 5 degrees off centre then grab or lock both. Basiclly a total of about 10 degrees movement back and forth with one wheel on the ground. This happens with both sides. I'm still getting posi, however one side seem to "bite" a little later? (yes in gear, and no driveshaft movent when wheel moves)

Question: bad cones, backlash setup, This is suppose to happen?

There no "bad" noise...clicks, thumps ect....well maybe a tad going into gear. Other then that just the regular old noisey 8.75 hum.