No, the splines on the shaft engage the splines in the engine crankshaft. In order to grease them, it is necessary to remove the gearcase. IMO they seize together because of the salt water spray that would be in the exhaust system, and because the crankshaft and the shaft are different materials. It is not necessarily rust accumulation but actually the buildup of salt that causes the problem. A word of caution here, do not grease it excessively at the top of the splines, as it may not all squeeze past the splines and not allow you to fully tighten the gearcase upon reassembly