That wasn't a difficult fix, thanks for the link. Now, 4High engages much sooner ,before pulling the level all the way back. Before, I had to pull hard all the way back for 4high, and the 4wd light would flicker. You can feel a positive engagement now, and seems to have corrected the problem. In fact, if I go all the way back, I have to go forward just a hair to get 4high engaged.
The only issue was getting my wife to hold the lever in the correct position while I tightened the nut on the linkage. The comments of "Are you sure you know what you're doing ?" weren't helping matters.