Old Snapper Zero Turn Spindle Housing Lubrication

I have been periodically pumping 10 pumps of grease into the three spindle housing zerk fittings, but there is never an indication of overflow, nor does the Owners Manual lists a capacity. The one on the left (see photos) is making noise during mowing that I can hear over the roar of the motor while wearing ear muffs. So I am greasing it more often and up to 20 pumps, but don't see any flow from underneath the deck. . I'd like to replace it, but cant find a replacement. Model Number MZM2200KH (84412) single joy-stick control. Anyone help with a parts source of maintenance option form this old girl?

Bearings do fail...Replace bearings. Should be 6305-ZZ bearings if research is correct as OEM bearings are NLA.

Thank you. Ordered two Timkins via Amazon this morning.