I did this on a 124 chassis. MB charges about 130 dollars for this job. You need two large diameter washers, one metal spacer bushing with an ID greater than the OD of the shifter plastic bushing you are inserting and a nut and bolt that will fit nice and tight through the washers.
On one side of the shifter arm, place the washer and the shifter bushing. On the other side place the spacer bushing and the other washer. Thread the bolt through all of this and tighten it up with the nut. Now once the nut is hand tight, keep on tightening with an appropriate spanner. Sooner or later the shifter bushing will pop through.
Not the easiest place to get to and make sure the area is cool but I did not need to drop anything.
Hope this helps.