I have been getting a clunk in my left rear when I go over railroad tracks or the curb in my driveway. I thought it might be my control arm bolts being loose, but I checked the torque on all the suspension bolts in the rear and none were loose. My springs are also in the right position. I was curious as to what this would be. And while checking, I grabbed each rear wheel and noticed that the left rear had some movement in it. I took the wheel and rotor off and found that my axel can move in and out of the rear end about a 1/16 of an inch or so. The right axel does not do this. Is this bad and what is the fix? Worn c clip maybe?
Was going to the track tomorrow night but not sure if I want to until I find out if this is bad or not. Also would like some advice as to what the clunk noise is...Thanks!

 

It should move in and out slightly like that, I'd be worried about the one that wasn't, since you need to push the axle in to get the c-clip out usually.