Does anyone have any idea why overdrive would be gone all the other gears work fine, just not o-drive.

A stripped gear maybe. Do you have a switch to turn off Over Drive or is it another selection on the gear selection? If you have a switch then it might be an electrical issue, but if you dont it kinda sounds like a stripped gear or a synchronizer issue. When you select o-drive is it like putting the truck in neutral?

Yes, I have a switch and it is like putting the truck in neutral. I took it to have to codes ran and it says 2 sylonoids and tourque converter, but I can't imagine all 3. I hope its something simple like that though.