Rear Shift Linkage Cup. It is at the end of the shifter rod. For 83.5-91 Vanagon waterboxer. Many times if you have play in the shift linkage, it can be traced to this cup or the ball that goes inside of it or both. They act as a mortar and pestle and if can dirt gets inside it will grind and grind until it wears the ball and cup and allows for more play in the shift linkage. I would also replace the shift lever and the boot that covers it to tighten up the shifting and keep dirt out to prevent it from wearing out in the future. The OE version of this is discontinued, I am going to start supplying the aftermarket one that is billet aluminum. If the OE becomes available again, I will go back to that.