My 99 F250 is not shifting out of Overdrive. Even from a dead stop, it takes off in Overdrive. I can put it down in 2nd gear and it will take off, then shift manually up to Overdrive (skips drive completely) and if I try to take off in 1st, it starts out in 2nd. Also, my overdrive button lights up properly when pressed, and depressed, but it doesn't activate anything.

My battery light is on as well.

Any thoughts?

 

Since the transmission is electronically controlled, I'd fix the "battery light" issue first and see if that resolves your shifting problem.

 

I thought the same... The battery has died on my twice now. Could it be the alternator? If it isn't charging properly, could it cause my transmission to not shift properly. Is the power to my tranny coming from the alternator or battery... perhaps the battery's only job is to start the engine and provide power when the alternator fails?

 

The alternator's primary function is to recharge the battery. Nearly all of the truck's electrical system runs off battery power. If you are having persistent electrical system issues, then you need to find out if you have a bad battery, failing alternator, or some other kind of issue such as excessive drain or short in the wiring.

Electrical system problems have definitely been documented as the cause for erratic transmission & engine behaviour. The computer expects to see certain voltages & amperages from the various sensors throughout the drivetrain. If these electrical values are not within range, all kinds of strange things can happen.

 

2nd and 4th gears only are a symptom of no electronic control to the transmission. That is failure mode for no electronics so that you can limp to the nearest service facility.