Assembling the shift cam. In this photo, the downshift lever has been removed for clarity. First install the cam in the position shown. (Note that the holding pawl has not yet been installed; this gives a bit more freedom of movement.) Install the cam pivot, positioning it so that the slot on the bottom engages the tab on the cam return spring. Twist the pivot slightly clockwise while pushing down, until it seats in the four slots on the bottom of the housing. Then, while holding the pivot down with your thumb, pull the cam back until it snaps into position and stays there. You can then install the holding pawl.

Assembling the shift cam.  In this photo, the downshift lever has been
removed for clarity.  First install the cam in the position shown.
(Note that the holding pawl has not yet been installed; this gives a
bit more freedom of movement.)  Install the cam pivot, positioning it
so that the slot on the bottom engages the tab on the cam return
spring.  Twist the pivot slightly clockwise while pushing down, until
it seats in the four slots on the bottom of the housing.  Then, while
holding the pivot down with your thumb, pull the cam back until it
snaps into position and stays there.  You can then install the holding
pawl.