I meant an air actuated inner hub release system that is engaged when put in 4wd, not an air locker. it will release the RnP/driveshaft from spinning except the axle shafts. as far as I know some jeeps had it and some blazers as well. which years, I don't know. either way, building a ghetto fabbed driveshaft that won't wobble can be done. if you need a hand, I don't mind helping.