Farminghandyman, I agree with you. The gear appears larger than the gasket and therefore it is unlikely that the unit can be withdrawn through the hole. Also, it would be difficult to verify that the injector gear is timed with the driving gear. I would want to put a number of witness marks on everything prior to disassembly.
http://jdpc.deere.com/jdpc/servlet/...ets.PrintPageServlet?printParams=Illustration
http://jdpc.deere.com/jdpc/servlet/...ets.PrintPageServlet?printParams=Illustration