While that squeal does sound like the center bearing, the "random clunk" sounds like what I had on my '84 300Dturbo (375,000 miles!). I pulled drive shaft and axles out to inspect only to find all was well. Clunk turned out to be caused by vacuum leaks that prevented proper shift modulation....do all of your vacuum driven systems work (door, fuel door, trunk locks, climate controls, brake assist, shut off)? I was certain it was a bad U joint or CV joint but it was just a vacuum leak! F