Hi all, there was a former thread with this title. It's a difficult job and just not evident on how to approach it. The 2012 uses aluminum gears and as pointed out, steel screwdriver leverage can cause some damage. However, the gear does NOT have any lip to clamp to, as suggested.

What I ended up doing was pure elbow grease. Get it 1/3 of the way on, push really hard onto the crimped part which is still "off" the gear, and turn the pulley or pull the belt as hard as you can with your other hand. To do this, the planer must be on its side, gear facing up. To put the most weight, the floor is preferable. I didn't get it for 3 tries, but felt it starting to WANT to go. Once you're past the halfway point, you just have to turn; it won't pop off. In other words, the pressure against the belt AND turning only has to last for 1/6th revolution.

Then I used a block of wood to set push it to the right alignment on the splines.

The vice grip trick gave me the hint that there was just no tool-based approach possible. Much appreciated.