Phillip, here is a link to the service manual for the mixer, it will show you how to take the mixer apart, replace the speed control lever and put the mixer back together.
http://lib.store.yahoo.net/lib/mendingshed/kitchenaidservicemanual.pdf
Thank you,
Colleen
Customer Service
MendingShed.com
800-339-9297
Colleen, April 2013