How are so many people breaking shear pins? My snowblower has inhaled tarps, newspapers, enormous ice chunks, rocks almost every time I use it… never broke a shear pin. What’s the deal?
The deal might be that your auger is rust-welded solid to your auger shaft. I see this on older machines. You don’t break shear pins because the shear pins aren’t what’s holding your auger in place, but if you keep busting rocks it’s your auger gearbox that’s going to go to hell.
Remove all shear pins and see if you can spin the augers on the shaft.
If your machine has grease fittings on the auger shaft, grease them.
Also, are you the original owner of the machine? See the above comment about rigging job artists replacing shear pins with hardened bolts. Any chance somebody did this before you got the machine?
Auger gearboxes are very expensive. I did a Toro gearbox a few years ago and it was over $300 plus tax for the gearbox.