old post on tandem axle Might try the big bolt boys, they have seen most of everything, including the weird not me

These are both tandem axels, after researching, I see yours is a real swivel frame (never heard of this before) Here's some information I found, you probably have seen the same thing, but this will let others see what you're talking about. Post some pictures of what you have! pix

Truckstell axle

Swivel frame by Truckstell
Truckstell #2

Swivel frame in action - powerwagon

Willock Manufacturing company it's a Canadian company

How it works