Unfortunately, the tranny does not go together that simply. You need to have the countershaft gear cluster laying in the bottom of the case so you can properly assemble the mainshaft on top of it. Then you turn the case over and let the countershaft slide down into position, then slide in the spindle. It's a very annoying and tedious process. I tried to shortcut that step and take out and reinstall the mainshaft leaving the countershaft alone as I wasn't doing anything with it, and found the parts just wouldn't quite go with the countershaft in position. To keep the bed bushiings and needle bearings in place (in addition to heavy, sticky grease) you'll need to cut a tube or dowel, the same or slightly smaller diameter as the spindle, just long enough to hold the end bushings in place as the countershaft slides back and forth in the case. When it drops into place you push the dowel out the other end with the spindle.

PS - Instead of typing all that out I should have just referred you to the article Phil has at the VClassics site: http://www.vclassics.com/archive/tranreb.htm

I printed it out and had it laying on the bench when I had mine apart. Very nice article.