There was always a similar issue with the Peerless manual transaxle - all the Bentonite grease dried out and plasterered around the walls of the casing with the shafts and fears revolving in an unlubricated void in the centre. We used to leave the Bentonite in place but partially ill the void with a mix of semi fluid grease and whatever EP oil was to hand.
Worked a treat , quiet easy shifting.
Where there's a worm gear involved fluid grease with a squirt or two of Moly Slip seems to work well.