I just rolled over 200K miles and just ahead of this accomplishment I started to feel a scary and almost uncontrollable movement as the car shifts from 2nd to 3rd (I use the automatic than shifting). It feels as it the car is starting a movement from right to left and it just feels out of control; its not subtle but extremely noticable movement (no jerking).

The other odd happening is occassionally going over a somewhat bumpy road, and traveling over 45MPH, the car has a similar movement and again the feel to me is "the car is out of control."

I'm not a car guy as you can tell from the very technical write up above, but does anyone have any ideas as to what is happening?

Thanks
BLP