Need knowledgeable OMC gearcase help

[gotboostedvr6]

I have a late 70's 25 hp tiller and am in the process of a complete rebuild... I'm 90% done but while i was replacing the WP the drive shaft slid out there are no clips or pins that hold it in so i doubt it sliding out hurt anything.. i slid it back in and it spins fine but now it makes a gear clack noise when i spin it.

It resombles a gear thats lashed too loose the harder i push on the splines the more "clicky" it gets. this is not the first time Ive seen a omc drive shaft that was removable and never encountered this issue during install.

it is installed in completely and the gear shift works fine... what can i do to remove the click?

[gotboostedvr6]

this gearcase does not have through hub exhaust