Ramcharger vibrates after using 4wd

87, central axle disconnect. Im thinking its still engaged. Vibration in seat or steering wheel? Bad axle u-joint im thinking.
Vibration is in the seat. Steering wheel still smooth-ish. 4wd lever is making a lot of noise and shakes much more. Axle u-joints are fairly new, and the rear joints are new. I don't feel any binding in the knuckles when I make a sharp turn like I do when the axles are locked in.