Hi, I am going to be attempting to replace the flex joint on the driveshaft of my 1995 E320 wagon this weekend. It looks fairly straight forward but I just wanted to see if I could get any hints or tips before I jump in.
It's more of a pain in the butt than you might think. Are you replacing the front flex joint, the rear, or both?
The problem is that the transmission tailshaft and the differential pinion shaft each have a long protruding nipple that slides into the ends of the driveshaft. Therefore it's not a simple matter of unscrewing all those flex joint bolts and simply dropping the driveshaft end. It won't drop and you can't slide the driveshaft forward or rearward enough to disengage. You may have to disconnect the driveshaft center support and that is a pain to access with the exhasut system being right below it. I can't remember the way Idid it last time but I think you get the general picture.
I assume you are doing the front. It's not easy but not all that tough either. True that it doesn't simply drop in but you don't have to disconnect and shorten the driveshaft - you can lower the exhaust and an exhaust shield you can pull the driveshaft end down far enough that you can slide the flexdisk in and out at a 45 degree angle. It's probably a couple hours of good work. Of course you need to have the driver's side rear wheel off the ground so you can spin the driveshaft to get at the flexdisk bolts. It's nice to have a racheting box wrench.
Flex Disc 
Linear Mode
