I have an old "year unknown" Craftsman, 28" - 9 HP, that had a transmission failure years ago, and I found a replacement transmission, but am having trouble figuring why the shift linkage is not shifting the transmission. It has a simple transmission with a plunger that slides in and out to select forward, neutral, and reverse. The gears are supposed to be shifted by a rod running down to a flat link which rotates a pipe with a flat piece on the end connected to the shift plunger by a chain link. It looks like the flat piece should push and pull the plunger, but it does not. Any idea what I have not done, or may have done wrong? I can move the plunger in and out by hand to manually shift the gears.