I have 2003 Z-71 with about 3000 miles on it and have noticed something odd in the last few days. When I leave my driveway the roadway I enter is at about a 5% grade. If I go downhill I have noticed that the Transmission is not shifting unless I let off the gas momentarily then it will after that hesitation. If I don't lift it will get to 4000 to 4500 rpm before shifting. Fluid levels are all OK and this only seems to do it when I go downhill. If I turn the other direction when leaving my driveway (uphill) I haven't noticed the problem. Any Ideas?