on approximately my fifth visit to the coupling with levers, hammer, and penetrating oil, i got it slid off. no work was required inside the firewall. i put a steel plate between the two sides of the upper half and drove the allen bolt into it to separate them. that seems to have made the difference. damn, was that sticky.

then i dropped the steering box, not quite as carefully as i had hoped, but carefully enough that no harm was done. a length of 4x6 lumber helped. moving forward!

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'77 240D, 504H, OM617.952, etc.