RE: Severe Vibrations
How do you mean the gear is hitting the frame?
If the top of the gear is hitting the frame there is suppose to be a spacer between the top of the gear and the main bearing.
Measure each side of your flybar out to the paddles, they need to be exactly the same on each side.
Are there weights on the flybar? move them in all the way and see if that helps.
I would remove the main shaft and make sure the spacer is there and roll the bare shaft on a piece of glass or a mirror to make sure it is not bent.
I would check the feather shaft as well.