To begin with, it isn't linkage it is a cable. The plastic that holds the cable in place is probably cracked and broken.The easiest way is to buy another shift cable annd replace the old one. If you look under your dashboard on the top left of the steering column you should see a very small cable looped around a little metal peg, slip that off then crawl under the pickup and on the left side of the tranny you will see the other end of that same cable. disconnect it and install the new one and your on your way. Good luck.