Does the 2015 Ford Explorer XLT have automatic overdrive or is there a way to turn it on and off?

My my new pickup it is a button on the end of the turn signal. Check there.

No button on turn signal lever.

OK, If it is not there consult the owner's manual the location will be listed. The vehicle has to be taken out of auto OD when towing or frequent shifting will occur. If you cannot locate it in the manual, call the dealership. It's going to be a button located somewhere on the dash or possible the steering wheel since you have an XLT.

Also check the column mounted shifter or the shifter handle if it is located on the console.

Shift it out of o.d. Go to 3 instead and it won't go to o.d. Or next gear down if you have more than 4 speed.