Crawl under your van and check the linkage points along your shift rod. It
sounds like something came loose, hopefully just the clamp pinch-bolt which
holds the shift rods together. Look at the shift rod and determine whether
the clamp pinch bolt or any of the connections appear to be loose. If
something is loose, you will still have to get things back together
correctly. I recently used the Haynes Service and Repair Manual to adjust
my linkage and found it to be a very good guide. Let us know what you find
along your linkage.

Dan Roberts