I found the problem. It was a bushing or spacer that wiggled it's way downward into the oils. I don't know what I was thinking at the time, but i removed the shaft and for some reason I had the urge to just shove my finger(s) in and feel around to see if there was any obstructions. Sure enough, in the empty space that's supposed to allow the shaft to move into the top gears, there was a spacer. About a 1/4" thick washer-looking thing. We got it all fixed up and put back together. It all works now. It would be a great help if the manuals included pictures of the actual shifter, rather than a shifter for other car models. The spacer I found was nowhere in any of the manuals and I couldn't find any online reference to it. If I knew what parts were supposed to be in the shaft assembly, and compare it to the parts I have, that would have helped greatly. Thanks for all the help guys.