Though the worm gear and tine shaft are shown to be installed in these photos, they should already be removed from your tiller by this point in the procedure.

Use a pair of snap ring pliers to remove the retaining ring from the bottom of the worm housing.

During reassembly, ensure the worm shaft is sufficiently tapped up into the worm housing before reinstalling the worm disk and retaining ring so that the ring properly sits into its recess.