Shift question

[the0captain]

I recently bought my first lincoln ls. Its a v6 auto and i have a question about how it shifts. When it is in D5 or D4 it feels almost like it has a shift kit(very firm shifts) at light throttle and the 3-4 shift is "jumpy" for lack of a better word. The shift kind of feels like you are driving over railroad tracks. Odd thing is if I turn the traction control OFF the 3-4 shift seems fine. I'm not sure if this is common or not.

I hope that makes sense lol.