I did a detailed write up on the manual furler overhaul, not the motor gearbox.
It's pretty simple. Remove the cover plates, you'll have to pry them off carefully. Inside you'll find a worm gear that drives a large bronze gear on a shaft that turns the furler. This bronze gear is known to wear out, so I replaced it while I had it apart (sourced from Amel). You'll also need the oil seals. You need the bearing puller to remove the bronze gear, and the top and bottom bearing. I understand that they were originally filled with oil. Following advice on the forum I filled them with grease. Many people installed grease zerts so they could top up the grease. While I had them off I painted them, many people have them powder coated.
