The hub nut measures up at 1 3/8 in. The parts store doesn't have a socket that size. The conversion comes close to 35 mm but a 36 mm socket did the job well; only 32 mm and 36mm are available at my parts store.
Turns out I can access the drivers side ABS wheel speed sensor without removing the rotor; it is located behind/ under the brake caliper. It looks like the passenger side might require the rotor to come off; here's hoping that sensor is OK. The rotor on this heavy duty wheel is held to the hub flange by the press fit of the eight wheel studs. I don't have a decent exploded view diagram here but it looks like maybe those 3 or 4 bolts 'on the backside', have to come out and then the rotor can be separated (if desired) from the rotor/hub unit by pressing the wheel studs out (or maybe by threading a lug nut on the studs a ways and driving them off). It looks like there are a few different 'Series' of configurations. Mine looks like it might be a 'K Series' configuration; 8 bolt, 8600 lb GVW.
According to my parts store, this particular truck (K2500) does not have wheel sensors at the rear wheels, nor could they find a VSS (Vehicle Speed Sensor) listed for the tranny. It seems logical though, that there would be some kind of VSS in the ABS system for the control module or unit to monitor the speed of the rear wheels. The use of a VSS on the tranny has often been discontinued in favor of individual speed sensors located at each wheel.
I will have to buy a new sensor for the driver's side wheel ($70) because it has a longer electrical lead than the passenger side ones I got from the wreckers. The wreckers are worth a try though, if they are easy ones to get off.
I will submit the ABS system results when I get the sensor in, put the fuse back in, and plug the ABS control unit back in.
