Tough to guess without knowing what kind of truck it is (coil springs so probably a Dodge) but it looks like a D44 with a central axle disconnect. That could be a guard over the actuator, can't see the actuator to tell if it is stock or an aftermarket version.
Looks like one of those old Detroit electrac units.
It's a Detroit electrac. I thought I had the only one left. It looks exactly like mine, I think it's the only one with the new diff cover and actuator guard. If the wiring posted doesn't answer any questions, I have the instructions that came with mine, I'll post up whatever you need.
It's a Detroit electrac. I thought I had the only one left. It looks exactly like mine, I think it's the only one with the new diff cover and actuator guard. If the wiring posted doesn't answer any questions, I have the instructions that came with mine, I'll post up whatever you need.