Yesterday I got off of the highway going to take my mower to the dealer for a tire repair and the light traffic light was red so I stopped of course. The light turned green and I hit the gas and I didn't move. The RPM's went up but I just sat there and then it finally after a second or two it kicked in and I was on my way. Is this a sign of the transmission going bad? I've got about 99,500 miles on it. Its a '05 Chevy Silverado 1500HD 4x4.