What if you unhooked the vacuum source to the switch on the transfer case and rerouted it to a solenoid that was tied to a switch in the cab, then ran lines to the CAD? When the switch was off vacuum would hold the CAD in 2WD, switch on solenoid activates and CAD slides into 4WD. A junkyard vacuum solenoid costs next to nothing and the rest is just some wire, vacuum line and a single pole/single throw switch. No cable to rust and freeze, no hassle adapting the CAD housing or shift linkage, and it's gotta be alot less than the $199 for a Posi Loc kit.