The answer to this is simple.

The mast enters at either the front or rear edge of the motor/gear box. Obviously the toothed wheel is toward the center from there. Insert the nylon cable so the teeth are toward the center of the box. This means, of course, you'll have to gain access to view the motor/gear box.

Note. If there's a broken piece of the nylon cable still in the box, you'll have to extract it before the new cable will catch. This happens.