Its really not that hard to take of the shifter. The description is on this forum somewhere. It start with two screws underneath the center console carpet. The carpet is not glued on or anything it just comes off.

Once you go through all the steps the nut is at the bottom of the shaft...make not of the orientation of the kink in the shaft, you'll need to remember it when you pu the new one in. It doesn't sit the way you thin it should sit.

You can buy a replacement shaft that accepts any mercedes shift knob from 97-2000 from www.************************ its not on their website you have to call them up. The part #SK33210 but confirm with them. If you want the original you can find it in many places including Ebay cheap.