subtle thudding in front end of 90

[Frank and Mary Avantaggio]

   recently a subltle thudding sound picked up in the front right end of my
90quattro. it only makes sounds on bumpy surfaces or when the car shifts.
it can be heard espsecially at low speeds below 30mph. i am not qiute sure
what it is, though i am almost positive it is not the cv joint because it
is not a constant sound ans doesn't always make noise when turning. if
anyone has any ideas it would be great. possibly a strut? 
  thanks
 chris