Sorry, I am in the process of moving my wifes stuff into the house, so I have no idea where that book is right now. If i remember right there are ball and plastic cups that hold the assembly together. You have to pry on them some how to get them to pop off. I did this years ago so its a little fuzzy now, but it was really simple when I figured it out. Just dont remove that nut, its impossible to put back on right, then it will just come loose again. I had to weld mine back together because the splines stripped when the nut backed off....basically its a pain.
Grab one of the haynes manuals if you can. I know some guys say they are junk compared to a shop manual, but I have had most of my problems solved by either it or the forums. The write up in the manual was good enough for me to get things back together. Unfortunately I bought it after I had things torn apart, the very first thing in bold is dont remove that nut.....I had already figured out why.
Do you have the metal plate? If so, look up a picture of the motor for sale on line. Line up the plate as best you can from the picture and place the plate on. Then tighten the crap out of it the best you can. Now one of two things will happen. 1. It will stay there and work. 2. It will work for a short period of time and then slowly stop working. If number two happens, then the splines have worn away because the plate became loose. If this happens, line the plate back up on the shaft and place a couple good tack welds to the shaft.
Thats what I had to do and its been working great for years now. Just try to line it up the best you can. If its off a little it will be okay, mine is a tad off and the wipers dont cover the original area, but its livable.