Have had about 3 instances, first with my dad's Montgomery Wards 8 hp lawn tractor with 42" single stage. We used this for years until I found a large rock from snow plow from village. Bent the high speed spinning auger/impellor unit. Never worked good after Dad had maintenance men put it on a lathe and ground off 1/2" of metal, still rotated out of round but didn't hit housing. Here in Salem had some huge storms, plowing and got stuck, pulled out by neighbor with John Deere 855. Went back to clean up lines where plow left behind and sucked in a 20' chain to my Yardman 13hp snowblower. Impellor housing raised a bit in the middle where chain went around. Had to break snowblower in two to remove and fix with new impellor. The housing is still raised, never pounded back down. Third time was in Greenwich, bought my Mother and Father in laws home, am naturally neighborly and snow blew woman next door driveway only to suck in welcome mat, luckily, only had to punch out both shear pins on auger. Spun right out with no damage to impellor. I did buy a 60" Woodmax blower for my John deere, works flawlessly, but worried about hitting something to damage gear drive.