my fiat uno 1100 shutters and doesnt want to move one inch after the shutter starts... i had plenty of advice... some say cv joints inner and outer needs to be replaced (the cv's appear to be fine)... some say buy a new gearbox(i dont know)... some talk about the shaft's ridges that are worn9the ridges looks still looks good)... and some about a box under the gearbox... now i am way to confused to even manage fixing the problem! maybe a lit match to the petrol-tank can work wonders! please help with advice.

The parts do wear badly and need to be replaced.
I got a rust free set fro Switzerland.