Tranny input shaft noise?

My buddy has a 98 Impreza with a manual tranny which has what sounds like a bearing noise only occurring with the clutch pedal released. It just had a clutch put in 20K miles ago and was fine then. Seems as though it would have to be the pilot bearing or the input shaft bearing. If it is the input shaft bearing is it possible to change that bearing without a complete disassembly? I can't seem to find any manuals or schematics on this tranny and was hoping the input shaft could be removed through the front of the tranny case without too much trouble. Thanks for any help

have you ever heard one of those bearings go bad? 2ndly, is it more of a whine? like straight cut gears? just thinking about all the bases.. im sorry and like you, i don't know much about disassembling the tranny