OK..the countershaft. First thing I did was remove the 6 bolts for the tailshaft. You then can rotate the tail shaft and use one of the bolt to hold it in place and you now have access for the other counter shaft bore. Apparently aluminum OD cases are "blessed" with a loose fit counter shaft, and a plug that seals the opening...what I did was drill a hole in the plug, and used a brass drift to gently push the shaft through the other side. A woodruff key will fall out. With the shaft out, let the countershaft gear cluster sit at the bottom of the case.
From the manual, rotating the tailhousing:

The plug (with hole drilled):

The bore the plug was installed in:

The opposing bore (note the notch where woodruff key sits):