3 on the tree grinding noise

When you hear this grinding sound can you also feel a roughness in the clutch pedal. Whenever I've had a bad throwout/release bearing I could usually feel it in the pedal when pushing down. I also suspect that your crank thrust bearing maybe be wiped which would explain the sound while reving up and the clutch pedal depressed. Also when hearing the grinding is your tranny in neutral or in gear.