New here. Saw the topic wanted to chime in..we bought a 2014 Silverado 1500 LTZ on the 30th of Dec 2014 as I was test driving saw the Service 4x4 signal I dismissed as I didn't know what it was. Had 26 miles when we bought it. Drove it another 10 miles took it back as besides that it would shift into 4 hi or low or auto. Took it back find it. 370+ miles so far so good. Keep fingers crossed, knocked on wood, poked the voodoo doll..lol jk.....maybe lol and all the good ju ju lol