So I either have:
-bad pinion
-bad rear axle side bearing
-worn rear axle pinion shaft
-worn cage
-excessive clearance between the axle and the side gear splines
-excessive clearance between the side gear hub and the counterbore in the cage
-worn pinion and side gear teeth
-worn thrust washers
OR
-excessive drive pinion and ring backlash

oh that really helps, I don't even know what half of those things are!!!!! LOL
Mine is not that bad and certainly only happens when I get OFF the throttle, so I might live with it for a while. We will see. Any thoughts?