Debbi

I appreciate all your input.  I'm not hitting any obstacles other than the occasional piece of ice.  Living in Michigan's snowbelt, we are always plowing snow 12" or more deep.  The augers seem to turn freely, but I'll get the grease to them just to be sure.

The original shear  pins looked to be made of a bronze type material.  Now when I buy the MTD brand pins required in the snow thrower schematic, the pins seem to be made of galvanized.  Good point about how tight the pins are, that's something I'll have to check.

I've considered going to a machine shop and having a gear custom made out of steel.  I'm not sure if this would damage the thrower or not.

I have a 20hp MTD tractor with a snow thrower.  The augers are protected by shear pins, however the shear pins are not breaking, the worm gear is stripping the large gear it fits into.  This large gear is made from soft brass, while the shear pins seem to be made of sturdy galvanized. 

My question is, why is the large gear made out of such soft metal.  Shouldn't the shear pins break before the gear strips?  Any opinions on having a gear custom made out of steel.  At $75 per brass gear, I can't afford to replace too many.  So far this winter I've replaced three.  Seems like the shear pins should be the first thing to break.  I'd appreciate any help you could offer.