Anyone have a source for the retainer for the back door?
The one on the 90 Monty broke and the door will not stay open by itself.

All the G1 SWB or LWB can source that for you. You must disassemble the entire door and remove from the rig to service that PITA.

Yes, I know how to get it- did so for the photo.
Is anyone parting out a Gen 1 that would have it?

Two weekends ago, this happened at The Ranch. Doh!

There is a remote change another still exists there. I did not see your pic, previously.

Interesting! Looks like a common failure. Inside the housing the sheared off there are two rubber blocks holding small steel bars that ride on each side of the long arm. As they pass over the wider parts of the arm, the rubber is supposed to compress increasing the friction of the small steel bars on the arm, which provides the resistance to the door closing. However, the rubber blocks get hard after 30 years so the friction on the wide parts of the arm becomes so strong that the leverage of the door force on the housing breaks it off the mounting plate.
Not only is this GEN I part not available from any Montero supplier, it is not even identified by a part number in the Mitsubishi shop manual or Gen ! parts list.

There's a couple guys breaking Gen 1's on the MMUSA Exchange page. I see a need for one of those in my future. I'm guessing the 37 hanging off the door has caused wear on one of the two sleeves and it's getting thin.