I had my shifter get real loose in the side to side motion recently.  The material that was bonded onto the shifter had worn off finally causing the slop.  This piece fits onto the end of the shaft to fill the void to tighten shifting back up.  I'm not sure how long it will last, but it works for now.  Printed in PETG

I cut off the excess material on the shaft and pressed this one on as shown in the pictures.