My truck will drive completely normal for a little part of the ride then after a little bit the overdrive light will begin to flash and it starts to shift really hard through every gear, mostly from 1st to 2nd...ne1 know whats up?

 

I had a similar problem withe my diesel f-350.The overdrive light flashing indicates a tranny failsafe mode.This is what i was told.You might have an issue with your trans.Best to bring it to tech.They are pretty involved electrically.I do know that there are speed and what they call turbo sensors on them that also go bad,those are easy to replace if you have the problem tracked down.But anyway in my situation i had my windshield replaced and water was comming down the colum onto my computer and jem module.That caused my overdrive light to flash and the truck shifted strange.Hope some of this helps.