My 2007 Ford Sport Trac 4x4 with 47K on it, has a loud whining noise while driving. I checked the wheel bearings and there is no play side to side or up and down. No noise rotating the wheels. I noticed that both drive shafts turn while rotating a front wheel off the ground. No dash lights are on indicating it`s in 4 wheel drive. Could the 4x4 shift motor be bad and not disiengaging 4 wheel drive ? Is there a way to check it ? Any suggestions would be apppreciated.

 

Is the noise present all the time, or only when turning? If this noise were due to always being in 4WD, you'd definitely notice it when trying to turn a sharp corner on dry pavement. The wheels would skip/hop and the turning radius would be rather large. You would NOT want to drive this on dry pavement any more than absolutely necessary if the 4WD is locked because that will destroy the transfer case and expedite tire wear.

If you carefully shift to neutral and let the engine return to idle does the noise change? If so, then the noise is not related to the transfer case or the axles/wheels.

-Rod

 

Thanks for your input Rod. The noise starts about 35MPH and gets louder as I gain speed and doesnt change if I turn the wheel left or right. There is no noise at idle, it starts when I accelerate.
I put it in 4 wheel drive and backed out of my driveway and it definitly engaged, because turning the wheel it did skip/hop, so I assume it`s not stayng in when I put it in Auto 4x4.
I`m going to check the fluid level in the transfer case and rear end. There are no leaks from either of them ! I`m wondering if the CV joints could be doing it .

 

Mine does the same thing but mine is locked in 4w auto and the transfer case motor is not plugged in so it can't shift (issues with transfer cm) if you find out what it is i would really like to know

 

I will gladly let you know if I find the problem. This drives me crazy not knowing what it is

 

Same here can't stand it mine is a 2002 explorer eddie bower 4.0

 

The rear diffs are known to get noisy. Try a fluid change and ask if Ford has an additive for it.

 

Tires whining? Bridgestones and other high mileage tires can cause a loud whine at highway speeds..