It looks like a gear or chain driven PTO (power take off) or a hyd. pump. The part on the back with the eyelet arm appears to be a braking mechanism with two pads and a rotor on the lower shaft. I could do better with more pix (all the sides and the labels too). I'm thinking atv, small tractor,,,,

It might also be a flux capacitor for the new Chevrolet Corvette Smart car hybrid.... the Smorvette (see pic below).

I'll give $1 for it. Is shipping free?

Bob