Yes, I plan on replacing that shaft. The threads for the the nuts (items 8 and 15) are already welded over. I think one nut is still on the shaft and it was used as a filler for the weld job. I'm certain I will trash that shaft getting it out, but really don't have much choice. I think it will cheaper for me to attempt a rebuild, only buying the gears and bearings etc that I need. 

Item 50 is the clamping nut that wasn't tightend up that allows the gears to float on the countershaft. See, I'm putting the parts sheets to use already!

I hadn't thought of cutting a pipe to make spanners. That I can do. 

Thanks for the parts breakdown. I appreciate it. 

I'll put up more pictures as I progress along.