Have someone watch the passenger side of the axle and the driver side near the frame. there is a bar that goes from the frame to the passenger side mount on the axle. THAT is your trackbar. There IS a trackbar on both leaf and coil spring suspensions. This keeps the axle from shifting left to right (keeps it centered). With 3 inches of lift you MUST have either a trackbar relocation bracket, drilled new hole for the mount on the axle, or replace all together with a new adjustable trackbar. This is not in question, or the axle WILL shift and be adding stress to the suspension components.
If you are not sure what you are looking at, or how to make the necessary changes, take it to a reputable off-road/4x4 garage and they can do it. I hate suggesting taking it somewhere since I do my own work (have turned EVERY bolt on my jeep and done all installations myself) but not all can do that.