I think a mechanicaly inclined person could.....
Pulling the trans is easy.1) unbolt the shift cable 13mm & 10mm wrench2) unblot the coupler, tool undetermined. Could be mm or in depending on what Hunter used. I've seen 14mm, 17mm, 11/16, 9/163) pull the shaft off of the trans, watch for water flow thru the packing.4) unbolt the trans from the engine. 12mm socket on about a 6" extension works well. There 8 bolts circumfrentialy on the bell housing.You MAY need to get forcefull with sliding the trans off the engine. The input shaft could be coroded to the flex plate. Take or send it to a Yanmar shop for rebuild.Install is just the reverse, remembering to put anti-sieze on the input shaft splines.Here's the hard part. If you've never aligned a shaft before, pay the yard to do it, ask them if they will teach you when they are aligning.Pat