I have a 2006 ss with a 2.4 and a auto trans when I shift into foreward it lags a bit like there is slop in splines but I took the axles off and they seem good
It's the same symptoms in reverse other wise it shifts great
Do you notice a clunk when putting it into gear? If not your axle shafts, possibly your control arm bushings might be worn. I found that on my daughters Ion, that by taking the tire while on the ground and rocking it back and forth, I could see and feel play in the control arms.