a single thump?? that would lead me to check the motor mounts. 3 of them, one on left side (on trans), one in front on right, one in rear on right.
if there was a cv joint problem, you may (but not always) feel a corresponding motion/vibration in the steering wheel.
also, check the ball joints and sway bar links, and control arm bushings. sway bar links would not be 1st on my list, as you would usually hear it on bumps.
Last, another thing that comes to mind.. not one I want to think about either, a failing strut in front (shock shaft starting to move fore/aft/side-to-side inside the assembly). remember, the upperend of the front suspension is held in place by the top of the strut shaft.
On replacing the motor mounts, right rear one isn't too hard, you can actually get to it when you pull the right front wheel off. right front is a bear.. the AC compressor is in the way. left one, I am not sure of, never messed with it.