Trussed and Spooled, or something...

I was looking online for toyota's, and some guy's offroad rigged popped up. I clicked on it, and his description said the axles were trussed and spools, or with spools. I know what the trusses are, but does anyone know what he was talking about with spools?

 

Only "spool" I can think of in terms of an axle is a diff delete. both wheels permanently locked together inside the housing, using a solid piece called a spool to replace the differential.

 

Real men run spools.

It's basically a welded diff. Both axles spin together no matter what.