I think this is the one:
http://catalog.eautopartscatalog.com/mercedesshop/sophio/quote.jsp?clientid=catalog.mercedesshop&cookieid=1JV0QMRTI1QU1B4K0K&baseurl=http://catalog.peachparts.com/&partner=mercedesshop&year=1989&product=J4070-44817&application=000046642
...and I believe there is also a clip.
I had my front flex disk just short of come apart on me, in mid February in mid week, in a nice snowy cold spell. So I gave the job to my indie. (Ahh the power of a lift and a warm garage in the winter) He replaced both flex disks, the tranny mount, and the lower shift bushing with the parts I bought from Phill just as the old ones started to crumble, for $150.00 labor. I can't tell you how much better it feels. Smooth non-clunking firm power.
I can feel a little hiccup back in the differential now so I suppose those mounts are next on the agenda. Wish I had done the job myself so I could give you pointers, but alas, I can only testify as to the results.