Sounds like a mount to me. The tranny mount is known to go soft(especially on the Zetec) allowing the tranny to rest against the engine cradle. It's easy to check. Just turn your wheel all the way left and look in the drivers side wheel well to see the side of the tranny. You'll most likly see the tranny is resting on the engine cradle right on top of the front most control arm bolts. If the mount is good there should be clearance between the tranny and the cradle. Another consideration is the two mounts that control forward and backward motion of the engine/tranny assembly. They can go soft allowing more movement int he whole assembly.
