My 1995 Jeep Grand Cherokee Laredo (6cyl, 4l) just started showing the "service 4wd switch" message, and then last night, it wouldnt shift out of first gear and eventually the transmission started slipping, and I couldnt go any faster than 5 mph. Had to get a tow. Please let me know if replacing the 4wd switch will fix this issue, or if I have a major transmission problem. Thanks.