Umm.. did you try this website?

http://www.searspartsdirect.com/partsdirect/index.action?psid=26128424&sid=PSx20071217x00001a

I have had no problems in the past getting parts for many of the Sears products.. What is the model number of the rototiller.

Note: In some cases, a bolt may be better than the normal sheer pin. Use a anti-vibration nut with a nylon end piece.

Depending upon type of tiller, model number may be between back wheels.