I have a 1997 Chevy 1500 4.3 4L60E trans. Yesterday While driving at about 40 mph the truck stopped moving and acted as if it was in neutral. After pulling over all gears are now acting like it is in neutral and it has no forward or reverse in any shifter position. The engine and trans were both replaced around 60K ago with new GM, and there has been no signs of issues such as hard shifts or slipping. It just quit all at once. Any ideal what the problem could be?I have checked the fuses and the fluid is full, looks and smells new and has no signs of wear or shavings.