3rdrecon, welcome to the HDTimeline forum, while others will weigh in shortly, can you clarify...1/8" play, are you saying the front sprocket moves on the shaft, like it has sheared something in the shaft or end play in and out?.
Is there any evidence of peripheral damage like this has been going on for some time or just happened when you were doing your routine maintenance? Do you have a service manual to help you see the internals before going in...?