Hello Gnuface,
There is one of these plastic bushings at each end of the linkage rod. They usually get bad about the same time. Notice that the new bushing has a smaller opening on one side. the small side should be installed so that it slides onto the metal linkage ball first. Use a lubricant which will not degrade the plastic bushing. I use a sunroof grease approved by MB for plastic sunroof parts, but I suspect auto trans fluid, Vasolene, CV joint grease, and many synthetics are suitable.
A lot of us use a bench vice and appropriate socket (from socket wrench set) to "press" the bushing into the linkage end. I think Alfred E. has a write up with photos somewhere on this site. Letting the bushings warm in hot water right before installation, will also make them more pliable.
Installation on the car can be more difficult. Squeeze it on with a pliers or pry tool.
The automatic shifter assembly has other bushings and soft parts in it also. These are not as critical as the two you are replacing on the linkage rod. These automatic shifters are more complex than you think. Inside you will find a light, rubber dust cover, plastic bushings, springs, clips etc. Take pictures of make a drawing if you get into it.
