Interesting mechanism here (I'm not 100% on how it works but seems to make sense). These came on my Ecuador FJ40 and from what I've read, they were produced by AVM in Brazil under a "handshake" license from Warn. Sounds like they didn't last that long and both AVM and Warn went away from these at some point. I'm in the early process of switching drums out to disc brakes on the front so decided to fully take this apart. Multiple roller bearings that sit around the outside. Appears to me when the axle is engaged and turns the inside of the this mechanism, the piece behind the bearings is like a 10 sided (decagon?) and it pushed up and engages the bearings against the outside. That's the best I can tell anyway. Does anyone have experience with these? Any references, I haven't found much? I have no big 4 wheeling plans so regreased, all surfaces look good, should continue to work as expected at this point (or not work since I won't be in 4wd much. Anyway, thought I'd post the pics as I find it somewhat fascinating.