James:
Type "shift lever lock" into the search box at the top of the page. You'll get two pages of postings, mostly on your problem, including a post by "Aye Roll" which has a diagram of the shifter quadrant (not necessarily your model, of course). The detail's not the best, but perhaps it'll give you an idea of the setup. By the way, there's one entry in the search result which suggests that the best approach is to remove the entire quadrant from the hump, and take it to the bench. As it looks (from the diagram)like the required adjustment is near the bottom of the stack, you may be reduced to this action. Try a few variations on the search subject I suggested, and also try Google, as it reaches out well beyond the common scope of our forums.
Good luck, and keep us posted.
Garth