While on an icy driveway, my 2017 F-150 (4-WD) rolled about 15 feet on the incline of my driveway. the only wheel that locked was the driverrs rear wheel. The other wheels were rolling free. This is very dangerous. Should I go in for service or is this to be expected?

 

That can be expected with an open differential or an unlocked e-locker.

 

Any vehicle that does not have a limited slip differential can do this. That's why you should always set the parking brake.

 

Mark and glc are absolutely correct. Always set the parking brake on an incline and never rely on the park pawl inside of the transmission.

Curb Parking: When you park headed downhill, turn your front wheels into the curb or toward the side of the road. Set the parking brake. When you park headed uphill, turn your front wheels away from the curb and let your vehicle roll back a few inches until the rear of one front wheel gently touches the curb.

Manual Transmission: Make double-sure you've got the parking brake firmly set. If on a hill, 1st or L gear if facing uphill; reverse if facing downhill. Just make sure to set the parking brake before releasing the clutch, so that the weight of the truck is on the brake first; the gear is there only as a backup should the brake fail.

4x4: If on a slippery or loose surface, keep 4x4 HI/LOW engaged when parking. On most vehicles it will keep the drive line locked in series. Still use the parking brake.