It will slide. Clean the tube shaft and lightly grease. Make sure the cap is all the way loose and off the ball collar. It may help to free it up on the transmission by putting some light upward pressure on it from a jack and block of wood. It maybe stuck there too and add a few light taps all around it. Wouldn't hurt to squirt some penetrating oil around the seal at the end of the cap area too loosen up the leather seal.
