1990 driver's seat recline stopped working

[Aurora40]

My recline on the seatback no longer works. I pulled the cushion off, the motor seems to run fine. And the seatback moves fine when I disconnected the rod from the seatback. What doesn't work fine is the rod moving through the square piece that the motor drives. I'm guessing whatever gears are inside the square part have seized up.

Even with the motor drive disconnected, I couldn't push the rod through it.

Is this part available? Is there some easy fix or way to disassemble it? I manually set the seat to a decent rake, but I'd of course like to fix this. Thanks!