New And Need Help

[Gunther]

Hi everybody. I'm new to the forums & am hoping someone can help me out.

I just bought a 71 C20 LWB. The problem is the passenger door. The rotating gear that latches onto the striker plate (not sure of the actual name for the piece) is rusted solid so the door won't open.

I've tried penetrating oil over the last four days & it just won't budge. Has anyone ever had this happen or know how to open the door without using the jaws of life?