I have a 2003 350z and my car starts and all but i just cant get into any gear at all. the car just rolls. any?

-is it an auto or manual? if its a manual it could be a number of things. bad master or slave cylinder, air in the fluid for the clutch. could be a trsmisson problem. same withthe automatic. if its a manual when you first get in the car before turning the car on shift through every gear several times without clutch, then do the same with the clutch then quit shifting and just pump the clutch alot then turn the car on then pump the clutch several time then try to put it into gear without forcing it. once into gear take it out and try putting it into other gears eventuslly it will go. if not then its a tranny problem. my 1990 nissan 300zx had this problemis it an auto or manual? if its a manual it could be a number of things. bad master or slave cylinder, air in the fluid for the clutch. could be a trsmisson problem. same withthe automatic. if its a manual when you first get in the car before turning the car on shift through every gear several times without clutch, then do the same with the clutch then quit shifting and just pump the clutch alot then turn the car on then pump the clutch several time then try to put it into gear without forcing it. once into gear take it out and try putting it into other gears eventuslly it will go. if not then its a tranny problem. my 1990 nissan 300zx had this problemsounds like an expensive transmission job