I have a 2001 that wouldn't shift into O/D. It was about -3 when i started it and drove it about 5 miles and it wouldnt go into O/D until I shut the truck off restarted it and then it shifted just fine. Anyone have any ideas or what I should expect in the future.

Might just be a cold related problem. I know that on the newer models, the computer won't let the trans shift into o.d. until it's warmed up to a certain temperature.