I need to change the gear shift that broke off in the transmission do i have to split it open all the way to change it

Craftsman tillers usually use a chain drive transmission. Sears does not usually offer individual parts for these transmission. They want you to replace the entire trans assembly. If the gear shaft is available (www.searspartsdirect.com) , then yeas, you would have to split the case all the way open to replace it. This is not an easy job. Most major repair shops would charge 4 or 5 hours of shop time for this repair. It generally requires complete dissassembly of the tiller to remove the transmission.

You did not give a model # for your tiller, so I am only giving you general solutions. Please look up the parts. Many times it is more cost effective to replace your tiller than it is to repair it. Remember that all of the other gear shafts are the same age as the one that broke and have been through the same stresses.

Good luck!