Wow.. not much to go on! Which grease fitting?
I looked up the first diagram i could find with some grease fittings on a tc-30 and it happened to be the 2wd steering parts.... all fittings on those diagrams were ID'd as:
1/8" NPT x 7/8" lg, 45' degree
you want more specific answers.. post specifics.. like which zerks are broken.
soundguy