Oh... so you don't actually know what it is?
What are the symptoms? If you're making a grinding/scraping/metal on metal noise while idling or driving you've got a bearing problem...
If you put the clutch in and it makes ugly noises, then stops when you let the clutch out, your TO bearing is shot.
If the clutch is out and it makes ugly noises while driving, not while stopped, then you have an input shaft bearing problem.
Hope for the TO, at least it's only a few bucks, get the one with the plastic sleeve inside, the one with the metal sleeve will wreck the tranny housing. If it's the input shaft bearing you probably will find yourself very nearly rebuilding the tranny. It's a stupid design, you have to crack the case and pull the whole tranny apart to change an input shaft bearing. In alot of old school v8 trannies you can simply remove the tranny and unbolt the bearing from the front of the tranny and replace it.
Don't ask me how I know all this :p good luck getting it fixed.