...as to your thread starter....
BTDT
My solution to prevent a re-occurrence was to have a machinist bore a 1/8th hole in the center of the pin and safety wire it.
(I removed the collar locking bolt/nut while doing the autopsy.)
I suspect the factory's three score marks were removed at one time, hence very low friction between the pin and the coupler.
...and yes, I had to drive home (240 miles) in just third and fourth gear.
Bill K
