One problem related to brake differential proportional valve has been reported for the 1999 Chevrolet Suburban. The most recently reported issues are listed below.
The service brakes have serious issues. Being in the auto service business for years I think I can safely say this problem stems from the proportioning valve in the brake system. Too much proportioned to the front brakes causes warpage and sudden vehicle jerk. A problem occurring in the brake system is as serious as it gets. A recall is in order! the slight cost of replacing above mentioned component is nominal compared to just 1 life (I. E. 1 consumer). I sincerely hope gm takes a hard look at this problem that has existed for nearly half a decade.