I was on the highway and my Service 4WD message center screen came on. After this, I switched (push button type transfer) it in to 4x4 and it seemed to go in and back to 2WD just fine except the buttons seemed a little harder to push than normal. Could this be the onslaught of a major mechanical problem or something electronic? I pulled over shortly after, switched into 4-Low and it was fine, light still on tho, put it back to 2WD just fine then turned the truck off and re started it, drove about another 30 mins and it never came back on. Perhaps just a fluke event? Thanks for any info provided.