RE: caliber 30 clutch failure
Your problem doesn't sound like it originated from the clutch. There are really only two ways you shear teeth. One way is to not have the proper clearance between the gears as they mesh. The other cause is your main rotor striking something, like the ground or the tail boom. It doesn't take much. The engine "scream" you mention was a direct result of the sheared off teeth.
Replace the gear and get back on the horse, once you figure out how to get it apart. Run a piece of paper or a .003 plastic shim between the gears before you tighten everything up. This will give you the proper clearance.
I'm sorry I can't help you with the second part of your question...I have not had mine apart yet.