Couple of thoughts on my part. Driver side bearing not fully pressed on axle would be the first thought. Secondly is it a sure grip? If so the clutch style uses a spacer pin in the center that floats between the axles to take up space for adjustment. I have had them fall out, usually find the pieces laying in the housing. Could pull axles and use a good light to look and see if you can see the buttons from each side of center section. Dr Diff has pretty good parts and I can’t see there being a difference on bearing thickness, that being said things do happen.
Differential Pinion Thrust Spacer Kit
