Hey Cygnus-

Actually, the Pulse Vacuum on the Super-Duties is new technology unique to that truck. Definitely not the same as the old S-10. The cool part is that if vacuum is lost, the hubs can still work.

I am not sure what your Chevy had. Some Chevy full-sized trucks (up to '97 or so)had a four wheel drive system that was engaged by way of an element that heated up and engaged a shaft. The problem was in cold conditions the element took forever to heat. Serious POS.

Some trucks, like new Jeep and new Dodge use a center disconnect system on the front axle. This uses vacuum or an electric actuator to slide a collar over the split axle shaft and engage the front-end. Maybe that was it.

Did your S-10 really have true disconnecting wheelhubs or was it some sort of center disconnect system?

Just curious.