That is the odd 5.5mm sized bolt, there are a few in the truck which require that odd 5.5mm socket.
The gear indicator tiny bolt is also that size, the one that mounts the fragile plastic part to the column. I only had one larger socket set which included that 5.5mm size, I try to keep that one in one place in my tool box. If you don't have one handy, it is a pain to find or buy one.