Well it looks like i need some more help,i replaced the drive shaft flex discs front and rear and center support and bearing on my 89 300se,loosened the slip joint nut to slide shaft back so i could remove it then replaced the front flex disc with lettering facing out and rear didnt seem to matter which way it was installed so i put it on the same as the front then i put shaft in vice and removed center support bearing and reinstalled new one and lined the shaft marks back up and put it back together and reinstalled it in the car didnt know if the center support waas adjustable or not so just tightened,then i tightened up the slip joint nut assuming the driveshaft was automatically where it should be and now i have bad vibration from 45 mph all the way up to 70mph and better as soon as i drop below 45 it all goes away,maybe somebody can help with this one as i have gotten a lot of good advice so far,just dont know where to go now,any help will be much appreciated,thanks.