The gear has it's key so fixed in one direction. It can't move in the other without breaking the auger gear case. The worm can't ride up over the gear unless it breaks the gear case. The condition of the auger assembly is the same as at the start.
The screw-hh's appear to be good. You would have taken them out to slip off the auger blades from the gear shaft so they are out as a suspect.
The impeller is mated to the drive shaft. Any impeller movement should move the auger blades. It won't be immediate. Some impellers move the auger blades in an 16th of a turn, other in almost 3/4'ers of a turn.
Moving the auger blades to make the impeller spin is hard. (But that can't happen anyway as your spin freely).
Moving the auger drive pully to drive everything is easier if the belt is not tight. You can take off the belt if there's belt resistance and move the auger drive pulley by hand. Make a pencil mark on the augers and then give the pulley a 10 full turns and see if the pencil mark moved.
There might be some friction around. You could wedge the blades with a board and see what that does to turning the pulley. If the pulley turns and the auger blades wedged you still have an issue. If you can't move the pulley then putting the belt on and firing up the system should move the auger blades. If not then the belt is slipping on it's v-pulley and you can see that with the belt cover off.
By the way, I put the auger gear case back in my snowblower today and it worked fine. I added a new auger drive belt. My problem was a bogus observation which I can't explain. As I explained in the other post I thought I saw the augers standing still while the impeller turned rapidly (a number of times).
I'm very interested to hear what happens with your snowblower. From the information you've given nothing was found defective and although the auger section disassembled and reassembled nothing was changed so the problem should still be there. There are no new parts other than grease.
This message was modified Feb 25, 2008 by trouts2