On my 1983 760 there was a clunk in the front end that turned out to be worn out calipers. The bore where the caliper mounting pins had worn so that the calipers were knocking when the car hit bumps in the road. I know that your later model 740 has a different style caliper mounting system, but since you have replaced so many other parts it might be worth checking out the calipers. I am assuming they front wheel bearings don't have excess play in them. Hope this helps you. John