URN (Unidentified Random Noise)

[eddiemoney]

Looking for ideas/help

2010 Expedition EL 4x4
30k miles

For the last 10-15K miles I have a very random noise I cannot place....I will do my best to describe it so bear with me:

Passenger Side
On interstate (anywhere from 55 to about 80 mph)
Typically hear when using cruise/light throttle
A whine/whistle type noise appears when coasting with very light throttle (can get noticeable loud)
Once the gas is hit harder the sound goes away, start to coast again with very light throttle it comes back

Sound doesn't happen every time....I can do a 300 mile trip and not hear it...or I could hear it 4 times in a 30 mile trip..it appears very random

I'm lost...no idea what it is....

Only hypothesis I have (and its not a good one): Could the wind be howling in something like the exhaust hence why I hit the throttle the sound goes away??

Your assistance and thoughts are very much appreciated

 

[eddiemoney]

117 views and nothing

 

[Whack]

Is it always while coasting, or slowing down without brakes?

Can you do it at any speed between 55 and 80?

Is there any vibration through the steering wheel?

Have you inspected the steering and suspension on the passenger side of the Expy?

 

[mindgame]

Using an CAI?
After market throttle spacer?

 

[eddiemoney]

Is it always while coasting, or slowing down without brakes?

Can you do it at any speed between 55 and 80?

Is there any vibration through the steering wheel?

Have you inspected the steering and suspension on the passenger side of the Expy?

It is usually when coasting or when very light throttle is occurring.

I only seem to hear it at interstate speeds (55-80) -> but I can't make it happen anytime I want, very random

No vibration at all...I didn't see anything out of place in steering.

 

[eddiemoney]

Using an CAI?
After market throttle spacer?

Everything is stock...nothing added or removed.

 

[Whack]

But an immediate throttle change makes it go away?

 

[eddiemoney]

But an immediate throttle change makes it go away?

Yes, as long as the throttle change is up 500rpm or more (estimating) the noise goes away

 

[Stoned06]

I see you said it is on the passenger side, but is it front or rear?

 

[eddiemoney]

Definately not engine bay/front wheel - somewhere behind that

 

[Whack]

What does you transmission fluid quality and level look like?

 

[Stoned06]

As far back as the rear axle, or just behind the engine?

 

[eddiemoney]

Fluids all look okay, nothing looks out of place...

As far as where...its very hard to place - It seems loudest in the second row

 

[Stoned06]

A light throttle whine sounds like it could be the differential whining caused by excessive backlash in the gears.
I had this in an Explorer I had. Coasting had absolutely no noise, light throttle had the whine, esp at higher speeds (50-70), and getting on it produced no noise (or at least couldn't hear it over the engine).
Put your 2nd and 3rd row seats down and see if you can be more precise in the location. Wheel bearing is also a possibility, but the throttle position makes me believe it is the differential.

Are you still under warranty?

 

[eddiemoney]

A light throttle whine sounds like it could be the differential whining caused by excessive backlash in the gears.
I had this in an Explorer I had. Coasting had absolutely no noise, light throttle had the whine, esp at higher speeds (50-70), and getting on it produced no noise (or at least couldn't hear it over the engine).
Put your 2nd and 3rd row seats down and see if you can be more precise in the location. Wheel bearing is also a possibility, but the throttle position makes me believe it is the differential.

Are you still under warranty?

Oh yes, still warranty (bought the 7 year because I don't trust Fords nearly as much as our Subaru )....but I always get leery about taking in random noises to the dealer so they can't reproduce

 

[PabloHoney]

I just bought a 2008 XLT with 109k on the clock. Only thing I can find wrong with it is the same noise described on this thread. Only happens when coasting. Touch the gas and it goes away. eddiemoney, did you even find what was causing the noise on yours?


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[eddiemoney]

Negative, been living with it for 50k miles, several years, and dealers never being able to identify any causals. It happens almost everytime I get on the highway. Very discouraging.

 

[stamp11127]

Depending on how bad you want to find it:

ChassisEar Squeak and Rattle Finder - Multi Mic Stethoscope (Steelman: model 6600)

 

[eddiemoney]

That's a lot of outlay for something I can find everytime I drive it, but the dealer used 200 miles and a whole bunch of gas for nothing.....computer mechanics vs real ones is my guess. I have money on some sort of transmission issue, but its not broken...

 

[mrford60]

take the tube off the throttle body and see if carbon is around the throttle blade. if so clean it out with carb cleaner and a swab. it could cause the wine