Only one comment on flex discs. MB made most of the late models idiot proof but there is a right way and a wrong way to put them on. If you look at the disc, it is often easy to see that there are three metal bars connecting the six bolt holes. The driveshaft is designed to be pulled by the metal straps; not pushed by them. On earlier models there were arrows disguised on the outside. Most later models have sleeves that keep you putting the right hole onto the shaft and flange.
[This message has been edited by stevebfl (edited 11-16-2000).]