[john walker's workshop]

those are not the detents you have to worry about. there are 2 others, one in the diff housing that needs to be between the two shift shafts, and one in the intermediate housing, in the flat end, which needs to be under the shift shaft, not toward the outside. they are contained in a drilling with a mushroom cap on the outside. they can't go anywhere, but they can slide up toward the cap and become useless as a locking device to keep two shafts from moving at once.