I just recently bought a 2003 Avalanche, and I was wanting to know if there might be some kind of recall on the 4WD system in it. You see, my "Service 4WD" indicator turns on once in a while, and I can't figure out the problem. My 4WD still worls, and it works fine, believe me, I've already tried it out, but I was wondering if the light comes on because I need to work on my transmission, or if it could be a malfunctioning sensor. If someone out there is encountering the same problem, and can help me, please do. I'd gladly appreciate it.