Very simple fix......

Dont know why people shy away from a future maintenance problem..........
IMO.

No Brainer here. No slop.
Just cut shaft about 1.5" drill hole if need to or allen key and lock nut provide stability.
$30 part
D

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Future maintenance problem?
Huh? Needing grease or a rebuild every forty years is a maintenance problem?

Drill for a grease fit at the bottom of the coupler, blow a load in it once a decade. No big whoop, and doesn't leave those of us that have seen the chassis flex in these cars shaking their heads.

I love watching people solve non problems. If you want to solve future maintenance problems, go after something like rod bearings next time.