the grind..., please help Options

[i_wanna_go_fast]

So heres the problem....

My gears grind.
The clutch is good.
Press in the clutch... to the floor, let off the gas... or vice versa... guess it depends on the driver... but either way... if i dont let the rpm's drop down low, the gears grind. doesnt matter what gear. doesnt matter if its up or down. only thing that matters is the rpm... if its higher they grind, if its low say below 2500 they don't. cant give an exact number cause whoever had the car before me put in new gauge faces and messed up all the needles...

could it be a flywheel issue?
shifter needs adjustment?
fluid change?

please help!!!!!!