If you make such a stiff dough then knead by hand. I did the same thing to my Kitchenaid a few years ago when kneading a too-large batch of challah. I have not damaged the replacement sacrificial plastic gear again (it's designed so just that cheap component will fail without causing more damage). I have taken apart lots of machinery and the inside of that Kitchenaid was beautifully made. I hope you repacked the grease when you reassembled it.

For pastamaking, I have an Atlas hand cranked pasta roller/cutter with various size attachments I bought over 20 years ago. It' all steel construction and will probably work for another 20 years.