Huh. From your description of all the minitruck parts I would have thought everything would work. The longer body Aisin/Asco lockouts came on '76-'78 FJ55s, and I think your only other option would be to find the longer body Warn lockouts for '76-'78 FJ40s/FJ55s.
I don't know if it matters, but is the lockout in the locked or unlocked position when you are trying to install it?
Rising Sun Bio
2F "Brahma" + Lockright, tach, Warn 8274, FJ60 Power Steering,
no more Sanden OBA
1FZ-FE factory lockers +
Safari intercooled turbo, CDL switch, cup holder, Metric TLC leather, heated seats, JDM switches, PUMA OBA.
Warn M12000 waiting for a bumper.
Limited TRD 2UZ-FE SOLD