I've got a strange problem with the transmission of my 2001 Chevy Venture Van. It has the 4t65e transmission that was replaced earlier last year. The problem that I am having is when I initially start the vehicle place it in gear and begin to drive, it drives and shifts fine (the shifts are a little harder than normal) and as long as I don't shut the vehicle off it will continue to drive and shift as it was built to do. Now, if I shut the vehicle down for a few minutes and begin driving again, it will shift once, that's it. Once I stop the vehicle and it cools back down (say in a hour or so), I start the vehicle and it will drive and shift like it is suppose to, but once again as long as I don't the vehicle down it performs as advertised. It doesn't matter that the engine is warmed up and has been running for a hour, it drives fine, but in order for the vehicle to drive like it's suppose to, I have to wait an hour or so. Anybody with similar problems?