My car was driving fine (03 6 speed coupe) and just tonight it started grinding going into third gear. The only way I can get it into 3rd is go shift very slowly... So is it my clutch or my transmission? It is the only gear that grinds.
Thanks

 

Does it grind going into third if you are stopped?

 

idk I will check it and see. It started with only doing it with a faster shift, and now I have to shift very slow.

 

The 3rd (and 5th) gear syncros are weak on our transmissions. It sounds to me like yours is going...

 

it doesn't grind when I'm stopped.

 

I would change the fluid and replace with Nissan's recommended fluid. It sounds like your clutch is ok as it is disengaging if it doesn't grind when you are stopped. Does your pedal come all the way up between shifts? If not change, flush, and burped your clutch fluid as well.