Wont shift into 3rd gear

3 speed 1980 ford f100. i can shift into first and second fine but when ever i try to shift into 3rd it grinds hard. i just got a new clutch too. any ideas?

Were you able to shift into third gear before the new clutch?

Linkage on the column or floor?

yes i was able to shift before. i brought it into the shop because one morning it wouldnt move. like i couldnt shift into any of the gears. it was like locked up or something. The linkage is under the truck so i guess the floor?

Sounds like a linkage problem, better than a internal trans problem.

Have someone move the shifter while you watch the linkage,look for levers slipping and not moving shafts.

ill check that out and report back thanks.