Chapman5.0

Well maybe not that bad but there is a problem. First snow here in Alaska and while driving to work this evening figured I would lock in the 4x4. Not the first time I have used it but the first time on snow and ice covered roads this year. When off the throttle all is normal, when applying the throttle I can hear a whirling or faint squealing but only in 4X4 and obviously in high. I have had several 4x4 trucks but have never heard this noise before. Truck is SC with 6 1/2 bed and only around 5k miles. Any ideas are appreciated before trying to diagnose and contact dealer for some help. I like to be as prepared as possible. Thanks for the help.

EricTheOracle

The noise is your transfer case making "I'm in 4x4 and goin' fast" noises.

Chapman5.0

Boy I sure hope not, if going 35 mph in 4x4 makes that sound it's the first I have heard in a 4x4. I looked like when I first heard the noise.

EricTheOracle

Where you in 4x4 low?

Chapman5.0

No sir. 4x4 high and speeds as high as 50 mph but probably averaged between 35 and 40.

EricTheOracle

Bring it in and while your there, drive another Ford F150 and put it into 4x4 on an appropriate road. My experience is that transfer cases tend to make a gear-whining noise when locked in.

Chapman5.0

Good idea, but I purchased this truck last spring and a few days later while trying to keep it looking so nice we recieved a good dumping of snow. I used the 4x4 on and off for the next few days driving the same route and no such sound was made.

caperJ

Use 4x4 here all the time no such noise, take it in get it looked at. I drive up to 100km (60mph) no noises sounds same as 4x2

maniacmikey

did you do any deep water crossings with the truck over the summer? I wonder if the transfer case is full of ice.

10-Ford

It could be a vacuum problem. The front hubs are locked in via vacuum, you may be hearing a vacuum leak or one of the hubs may not have enough vacuum and may be only partially engaged.
Sounds like a trip to your dealer.
Good luck