I have a 6speed Maxima that recently died out and no longer drives when put into gear...

Prior to this problem my throw out bearing was extremely loud so I replaced it and it went back to driving normally..

I dropped the gear box and put up a new flywheel, clutch, pressure plate.. and throw out bearing again.. I put everything back together had the car on jack stands still.. started it..

All I continue to hear is a loud whirring sound coming from inside the gear box.. When the clutch is pressed the sound gets louder.. and when in gear the tires dont spin and the sound stays there...

I was told it may be that the splines in the crank are gone and my input shaft bearing isnt grabbing..

Please let me know if anyone has any ideas...