need help find road noise issue
 

The noise is related to vehicle speed, not engine speed. Easiest to hear when all is quite coasting at 30mph. Sounds like the front. It just started the other day.
The noise sounds like moan from airplanes high ahead (think WW2 movies).
I replaced the front springs and shocks a few thousand miles ago and did not get it realigned. No noise until now. The tires are good and feel smooth (no sign of cupping, feathering,..).
It is 4wd.
How best to tell if it is wheel bearing? Rear end? Get it aligned?
Thanks

wheel bearings are a good bet...... You put a jack under the A- frame and lift the tire 2 inches off the g round. Spin the tire and listen for noise or drag. In the beginning stages of failure, it is sometimes hard to "feel" a problem with the brake disc/ caliper installed. You might have to take the caliper off and turn the disc and compare left to right to see difference in noise and or drag. ......... another possibility is the drive shaft universal joints... normally the rear joint ... but normally has a slight vibration also... you can drop the back end of the driveshaft off the axle and turn/ twist the U-joint to check for dry/ stiffness......... good time to wiggle the pinion shaft ( input to axle) also.

Thanks for the suggestions. The front driver side wheel does have considerable drag. I plan to take a closer look this weekend - I will let you know.

You can swerve left to right and see if the noise changes. This changes the load on the bearings. Swerving left loads the right bearing and vice versa. Be careful not to take out any mailboxes or small children:-X03:-X03

I took a closer look. A pad was dragging so I fixed that. Wheel bearing seem fine. Now it brakes better. Still makes the noise and swerving does not change the sound. At this point my guess is the front differential. I'll continue to drive it until the weather gets warmer and the noise becomes more noticeable. Thanks

The front differential shouldn't be rotating unless you're in 4WD.

Even though both front axles shafts are spinning you don't think the moan can be coming from the front differential???

The shafts don't spin when in 2wd unless there is a problem with the IWE system.

I assumed that the two half shafts spin with the front wheels, and engagement with the tranny was handled by the transfer case. What you are saying is that locking is at the hubs - correct? When I spin the wheels with the engine off, the half shafts spin.
I need to review my shop manual. :-X22

two things happen on the new design front engagement of 4 x 4... FIRST the transfer case motor engages the driveshaft to the front axle and the half shafts will turn.... second, there is a vacuum engagement on each wheel end called IWE that pulls the individual wheel in or out of 4 x 4... Normally the 4 x 4 is engaged at the wheel end.. When you start the truck and have VACUUM, the IWE is disengaged and back to 2 x 4... This allows it to be exercised everytime you startup the truck..... if it does not work 100% correct, you can get some dragging and noise........ you are correct, if you jack up the tire and try to turn it, the IWE is engaged and the half shaft turns... start the motor and the IWE should disengage the front wheel.

Well that is great to know. Thank you very much. So with the engine running and wheels down, I should be able to turn the half shafts by hand.
Thanks for the link.

Update: My half-shafts do not disengage.
I pulled the double vacuum line off the solenoid while the engine was running. Vacuum was getting to the valve. I attached the source line to the valve and there was no vacuum going through the valve. Bad valve. I put my vacuum pump on the other line and it held vacuum very well. So all I need is a new solenoid valve which I bought from Ford (or so I thought). Installed the valve and still the half-shafts did not disengage. Then I pulled the check valve out which was no longer checking. The line between solenoid and check valve was blocked which I cleared with a wires. I applied the vacuum hand pump to the line which runs to the actuators and I could not get any vacuum. Applied vacuum at each actuator, one leaked badly the other could not get any vacuum.

Since water was entering the system via a poorly located solenoid, my advice to others is that you inspect the entire system - you likely have multiple problems.

So I ordered 2 actuators. I will install them next weekend following FordTechMakuloco instructions

Yeah, you'll definitely have some noise turning the half shafts, differential, and driveshaft with the front wheels. Good that you found the cause. Also be sure you inspect all the check valves and replace if bad. Depending on year, there is 2 or 3.

A completed replacing my bad IWE actuators and verified that the half-shafts are now disengaged. YEH.

Went for a test drive and the noise is still there. Looks like we are back to the early stages of a wheel bearing failure. I will let it go for a few months and see if it worsens.