Do any of you know of common problems with the push button 4 wheel drive on the '99 Chevy Silverado? The only way I can put my truck into 4 wheel is with 'Auto'. The 4 wheel High, and 4 wheel low buttons do not engage the 4 wheel drive. I've been told as long as 4 wheel is still working with the 'Auto' button (It does work that way), It is more than likely just the buttons gone bad. I dont want to end up replacing parts that arent going to fix the problem. Anyone know if this is common?? Thanks in advance , Matt.