Rear end

[hangarb7]

Sorry if this question has come up before (I searched and could not find an answer...)

I put my car on jackstands and wanted to run the car to see if the wheels are bent. I was told the passenger side might have a wobble and I am installing new tires so I want to change rims now.

The driver side runs fine with the engine idling in gear. The passenger side doesn't. It moves about an inch and stops, then moves about an inch and stops..... over and over. I guess if that is a differential thing, I get it but is it normal to perform that way?

Thanks,

Jack