Thanks for the good ideas. I'll check into the mount bushings on the differential.
As for the question about the "S124", it seems that the proper chassis designation for the 124 series wagon is S124 and not W124. The W seems to refer to the sedan body and the S seems to refer to the estate or wagon. (C is for coupes and R is for roadsters I believe.) The mechanic that I take my 300TDT told me about this a few months ago as I had assumed that "W" was used for all 124 series vehicles.
Here is a link to a thread on benzworld about it.
http://www.benzworld.org/forums/general-mercedes-benz/1390480-does-w-stand-anything.html
Here is a link to an Australian website that mentions it towards the bottom.
http://www.mbspares.com.au/Information/Understandingchassisnumbers.aspx
The chassis series letter "S" of course is totally different than the letter "S" used in the model/class nomenclature that denotes the large "S" class sedans.
Please keep the ideas coming.
Thanks again,
-Steve