i have a 2003 g35 coupe - i start the car - press in the clutch (which feels normal) and try to put in gear and it just grinds - can't put in any gear - clutch fluid is full - is my clutch in need of replacement? THX for replies - btw clutch was last replaced 4 years ago

 

Just to rule out a transmission issue, can you engage the gear while the car is off?
If so, then it's a clutch problem (sounds specifically like a shift fork problem), if not..... Eh.. Hope you have some cash.