I have to disagree about the hubs on my Ranger. This truck does not have hubs, period. This is what is commonly referred to as the "live" axle design. The vacuum hub design was used from 1998 through early 2000. Begining in mid-2000 Rangers no longer have the unreliable vacuum hub design (PVH). As stated in my original post, the front axles and driveshaft turn all the time, they only have power applied when the transfer case is engaged in 4H or 4L. In my case, because the truck is a manual transmission FX4, the transfer case is also manually shifted. This is a much more reliable design than either the pre-98 auto hubs or the 98-2000 PVH system. The drawback is, of course, that there are numerous pieces parts turning all the time and these frictional losses decrease fuel mileage and increase part wear and tear. Oh, and by the way, I've never heard of "electric activated hubs". Exactly what are those supposed to be? The only three types ever used on Rangers from the factory were true manually operated, centrifically activated "automatic" hubs, or the vacuum activated PVH hubs.
Now, back to my original question. What type of hubs are used, if any, with the Control Trac system as used on the Explorer and Sport Trac?