I think there may be a better solution. (This quote is from my files. Sorry, I don't remember where I copied it from and don't have time to find it again)
"The shift linkage connects to the shift control shaft at the rear of these transmissions. The attachment is made by means of a roll pin through the linkage universal yoke and the control shaft. This arrangement is highly susceptible to wear on the shaft, universal and the pin, and a better arrangement can be had with the following mods.
Remove the shift linkage from the car (good opportunity to clean, inspect and repair). The linkage can be detached from the shift lever with a little effort through the access hole in the center tunnel. The middle pivot and the rear connection must also be detached. Then the whole linkage can be slid out the
back. Check the universals and rebuild as necessary. Also check the rose joint for the center pivot and the shoulder bolt and plastic bushings at the shift lever and replace if necessary. The rose joint is attached to the linkage with Loctite. Try a 1/4" bolt to see if it will fit through the hole in the end universal yoke and also through the hole in the shift control lever. If not, drill to 1/4". Saw a slot through the universal yoke on ONE SIDE ONLY located as shown in the photos. The yoke does not have a flat surface for the head of the bolt so you now need to mill, file, or grind the material away on the yoke so that a bolt through the holes has a flat place to sit. Reinstall the linkage and install a good - at least grade 5, and an AN bolt properly sized is better - bolt through the hole and secure it tightly with a washer and a nyloc nut - also grade 5 or better. The universal yoke will be tightly clamped onto the shaft and will no longer move around."