You can try to move the gears up, down left and right to see if they have any slack. That will tell you if it's bearings. The gear mesh should be very tight with almost no appreciable slack as they hold the timing of the rotors and if they are just the slightest bit loose you will have score marks on the rotors as well.
If the rotor pack is screwed then your pretty much hosed. You will need a new rotor cartridge. I used to buy them from a guy named Ed Morad, who I think was here. I think I paid about $60 each for them.
Jeff
