After spending two days googling and reading 17 pages on this forum alone I am still confused what is wrong.

The car: 2005 Si with 188xxx miles
The problem: We've owned the car for around six months and it has always had a balky shifter, so two weeks ago I drained the transmission fluid and put in 2 quarts of Honda MTF (filling until it started dripping out of the fill hole with the car level). The shifting was definitely better, shifting nice and smoothly, but then began getting balky again. The last time we drove it, my son began complaining that he was having a hard time shifting into and out of any gear so we swapped out so that I could experience it. Yea, we barely made it home, it was that bad.

Trying to diagnose it I discovered:
  • It will shift into every gear with the engine off.
  • If you start the engine with it already in gear (clutch fully disengaged) it will make a whirring noise that will go away as the clutch pedal is released.
  • If the engine is started with the transmission in neutral there is no noise but it will make the whirring noise if you try to shift it into any gear.
  • Once in gear with the clutch fully engaged, the car will move without making any noise.
  • The engine will stall if you fully engage the clutch with it in gear and the brake is on.
  • Fluid level is where it should be and I could not see the level rise when pushing and releasing the clutch pedal.

This is my son's first car and I taught him how to drive and drive a manual so I initially thought he burnt out the clutch, then after too much googling my suspicions changed to a CMC/CSC problem, then to a bearing issue. My head is spinning!