My '00 Tahoe 4WD has been making some pretty annoying creaking noises that seem to be coming from the front drivers side area when turning. It also has kind of a clunk when starting and stopping. I checked the main drive shaft and it seem those u-joints are fine. The front drive shaft u-joints also seem to be fine, though there is a bit of play at the output shaft of the transfer case. I haven't been driving in 4WD so I don't know if that would even have any effect? I've tried pushing and pulling on everything I can grab onto under there and I can't make anything creak. What do you guys think?