Probably just dried grease clogging things. Take the grease fitting back off, insert a small wire and move it around a little. Put the zerk fitting back on and try again. Sometimes it takes a few tries to get grease into a dry fitting with a hand gun. If you can get even a little fresh grease it it, it should help break down the crud, so try again in a few days until it flows freely. If you can't get grease into it, take it to a shop and let them try with the air gun. If they can't get grease in it, it's time for a new joint.

Frank

'89 [color:"white"]G-Raider[color:"white"] [color:"black"]Supercharged 3.0L, MegaSquirt 2, lockup A/T, 2.5" exhaust, 172k, Cibie H4s/Oscar SCs, Hella Micro DE fogs, Cobra CB, Superwinch hubs, LSD rear/Aussie Locker front, Bilsteins, Lifeline AGM, Rust-Oleum