Motor/Trans Mounts

What are the symptoms of a worn motor or transmission mount? I feel a distinct clunk when I place the car in Drive or Reverse from idle. I did not notice any problem when I bought the car few weeks ago. Before spending 300+ I checked for the problem one more time. The problem is that the clunk was all but gone. An intermitent clunk! What gives? Any ideas? The car is an '05 Malibu w/4cyl, 119k. The former owner had the transmission fluid changed at 94k.

Could be a worn inner cv joint