Small Engines (Lawn Mowers, etc.): snowblower vibration, briggs and stratton, shear pins

Question
hello
tonight during our first snowfall of the year i took out my craftsman c950-52430-3a snowblower.  after a few small passes in the yard i attempted to blow a pile of snow that i had shoveled off to the side.  immediately the snowblower stopped working and it felt as though i had hit something in the pile.  i started it up and the briggs and stratton engine runs fine except the auger has alot of vibration when i engage the auger.  i looked at the shear pins and they are intact.  i took the underside pan off and everything looks fine under there.  
can you point me in the right direction in what to look for?
i have the owners manual out and i will probable take the whole auger unit out to see what looks out of place.  

Answer

auger Hugh
There can be a few problems that you have the gear case may be damaged.
You also should check the belt that it didn't come off and is crooked,or it is rubbing.There are bearings also. try spinning the auger by itself to see if it turns smoothly.I have enclosed a diagram of the auger housing.