So yet another question on my 1989 Wagoneer. Putting it into and out of 4WD is sometimes sluggish, presumably because the vacuum system is not as tight as it could be. Is that true, or is there something else I should be checking? Or are these vehicles just typically slow with this? My old Cherokee that I no longer own was really bad about this. Practically impossible to get it into 4WD, and then again to get it out. My Wagoneer is not too bad, but sometimes it takes a while to get it out of 4WD.