I have a 01 tahoe with 133,000 on it. I know some people on this forum like me have been complaining about a ticking noise coming from underneath their truck. Some believe it's from the transfer case, and that can very well be it. I'm telling you to replace all your u joints before you spend alot of money on a transfer case. I just replaced the u joints on the front drive shaft and the noise is gone. This is a common problem with mileage like mines.