I have a weird pin box- tilts side to side

Fuel tankers used to oscillating fifth wheels all of the time, I don't know about anymore. Having the fifth whl pivot both directions prevented the tanker from twisting, or torqueing putting undue stress on it when the tractors wheels were tilted one direction and the wheels of the tanker were tilted the opposite direction. It made the fifth whl a little higher because it had to have room for the second pivot point, but it served its purpose on rough roads and un-even entrances into businesses.

Holland oscillating fifth wheel

Bill