[Bigdav160]

I have a problem with that thread. First, you can't properly set the preload on the worm gear with the sector shaft in place. The preload on the worm is essential to getting a tight box with no slack. Also it is very easy to remove the spool valve with the adjuster plug. BE VERY CAREFUL! The spool valve has to be aligned with two tabs and a very small pin on the worm.

I believe the overhaul procedures are all in the service manual.