I was under the impression that the vent window could not be replaced by itself. I pulled the entire vent window and frame from a donor door, with the intent of swapping it into my door. Came out with basic tools, pretty sure I just had a socket set along on that trip.
If the vent window wants to fall out, I thought that meant that the hinge bottom was gone/rotted away, and the hinge was part of the frame, meaning that an entire new frame assembly was required. Someone that's done this successfully clarify???