probably input shaft bearing in the transmission and not the throwout bearing - the throwout bearing only makes a noise when you depress the clutch, not with clutch pedal out - with pedal out, the throwout bearing is just sitting there doing nothing (unless, of course, you have a misadjusted clutch with no free travel) - with clutch pedal depressed, the transmission input shaft stops turning and if you have bad input bearing, the noise stops - let out the clutch and input shaft starts turning and with bad input bearing noise will start up