The stuff you are talking about in all your threads is all "compatible". It sounds like you have issues with your transfer case engaging 4WD. Try doing it by moving the lever on the case underneath. And if you are just looking for your 4WD light to come on, don't worry about that yet. Many XJ's (like mine) go into 4WD fine, but the light doesn't work. You also need to worry whether the axle ratios in the front and rear are the same. If not, it puts way too much strain on the transfer case (which is chain driven).