the gear linkage metal bushes usually rust with age and seize (mostly the universal joint near the gearbox cos its exposed) so the mechanism feels very resistive.
you'll need to take out all 3 bushes, clean, wirebrush n regrease.
the universal joint bush is riveted to the selector rod so you grind the smaller riveted head off (cos the shaft is stepped, look closely at pic) to disassemble. then replace with nut & bolt.
after removing the rust layer, the bush might fit abit looser and lead to difficult 1/2nd gear engagement and rattling 5th gear.
either replace the plastic outer bush, replace/remachine a new metal bush or modify into a better ball-bearing system which I'm working on at the mo and will post a guide soon.
