There seems to be a chronic problem to many 99-07 Chevy/GMC full-size trucks & SUV's w/ 4WD.  There is a lot of discussion on other forums (fsc.com), but no one has really detailed how to fix the problem.  Can you guys at 4Wheel & O/R take a look at this?  I would really like to see a simple how-to article that explains what this problem is & why it has existed for so long.  I believe GM has even released a service bulletin on this matter, but it does not cover all vehicles that are affected--such as my '04 Chevy Z71...