1992 Nissan Sentra Clutch

When i push the cluch pedal in it doesnt do anything most of the time but sometimes when i start the car with it in gear the cluch works but when i shift gears again or come to a stop it doesnt work. Also some times when i push the pedal in part way the cluch kind of works but never fully disengages. So my question is will i just replace the cluch plate or might there be problems with the transmission itself.

I have already adjusted the cluch cable and it did not have any afect and i know there is nothing wrong with the shift linkage.