Droning noise when letting off gas at highway speeds

[Mokume]

It's getting hard to tell what's real and what's not when it comes to tailgate damper commentary

Commentary aside, I'm installing one...that's my story and I'm sticking to it...

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[Toytec]

I wonder if this noise could be related to the dual drive shaft. Reverse of the slight shudder some get from a dead start.

This is where a diagnostic tool like 'Chassis Ear' comes in really handy. Wish I could help.

 

[Zaph]

I'd strap a camera that has a microphone to the rear axle and go for a ride. Close to the differential and and within good range of the exhaust. If there's something there, you're going to hear it when you play back. Then if there is something there, that video is your evidence.

OP: Don't get too excited yet. All might be normal. Everyone is really sensitive to noises.

 

[John Lyman]

Commentary aside, I'm installing one...that's my story and I'm sticking to it...

You won’t be sorry

 

[Mokume]

You won’t be sorry

I am certain I won't if there is anything I detest it is things that slam, automotive-related or otherwise.
My only wish is that the mechanism be hidden as in the F-series, but that would of, no doubt, incurred additional cost to the product.
The part is on hold at my dealer's part department, now all I need is the vehicle to attach it too.
Hopefully, that will happen on Sunday.

 

[John Lyman]

I am certain I won't if there is anything I detest it is things that slam, automotive-related or otherwise.
My only wish is that the mechanism be hidden as in the F-series, but that would of, no doubt, incurred additional cost to the product.
The part is on hold at my dealer's part department, now all I need is the vehicle to attach it too.
Hopefully, that will happen on Sunday.

Man the wait would kill me - but the wait is almost over - enjoy driving it this weekend and at least you are in paradise

 

[Aggie]

When you take your foot off the gas the engine is making vacuum. Maybe something is bleeding off the excess.

 

[Shermy452]

Did anyone figure this out. I def have it. And it's from the front for me. Wondering if anyone knew what it is. Might need to go back to the dealership ....

 

[P. A. Schilke]

Did anyone figure this out. I def have it. And it's from the front for me. Wondering if anyone knew what it is. Might need to go back to the dealership ....

Hi Shermy,

Sounds like the Blow Off valve.

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

 

[Cmar]

Turbo compressor surge maybe?

I don't think it's the tailgate damper, Anthony I found an error in one of your equations, line 14 the 1/4 should be Pi (22/7), tailgate damper is exonerated. ( Hope so because I want to put one on mine.)

 

[nny_ranger]

I am noticing the same kind of noise now at 55 and above when I let off the gas. The second I go back on the gas it goes away. I recently had my tires rotated while it was in the Ford garage for its third set of brake pads in 26k miles and thought maybe there was uneven wear on them.. I also just installed the Eibach rear shocks to improve on the FX4 shocks having too much rebound so I might swap the FX4 back in to see if I still hear the noise...

 

[Mokume]

I am noticing the same kind of noise now at 55 and above when I let off the gas. The second I go back on the gas it goes away. I recently had my tires rotated while it was in the Ford garage for its third set of brake pads in 26k miles and thought maybe there was uneven wear on them.. I also just installed the Eibach rear shocks to improve on the FX4 shocks having too much rebound so I might swap the FX4 back in to see if I still hear the noise...

Your truck has gone through 3 sets of pads in just 26K miles? Were they the front or rear pads?
At any rate, friction material wear at that rate is definitely abnormal, even or uneven.

 

[nny_ranger]

Your truck has gone through 3 sets of pads in just 26K miles? Were they the front or rear pads?
At any rate, friction material wear at that rate is definitely abnormal, even or uneven.

Haha you're telling me dude. So I am technically on my third set now. Stock ones were gone at 18k, replacements were gone at 25k. It is just the rear and the inner pads on the rotors. The Ford dealership has 0 clue as to what is going on and do not listen when I tell them they need to replace either my master cylinder or proportioning valve. They just keep throwing pads at it...

 

[tjanok]

Any update on this? I have this same issue. Shutter noise from the rear when deaccelerating when above 55mph. It's really really hard to pinpoint. Doesn't sound like a pinion bearing or a wheel hub, but close. It also only last for a brief moment

 

[CO2Ranger]

I was on a longer drive this past weekend on the highway and (for once) had the ratio off. I noticed that in the 70 mph + range when I let off the gas, I heard a droning sound from what sounded like behind me. The tone / sound almost sounded like when you drive over rub strips (but certainly not that loud). “mmmmmmmmm”

As soon as I put my foot back on the accelerator, the sound would go away. It would only make the noise for a couple seconds (perhaps once it gets below a certain speed?)

At first I thought it was my new tonneau cover making a weird noise in the wind, but that doesn’t make any sense (only when letting off the gas?).

It isn’t loud and you certainly wouldn’t hear it unless it was perfectly quiet in the cabin, but I’m kinda anal when it comes to noises I can’t pinpoint the source of.

Differential noise? Driveshaft vibrations? Aliens?

Thanks folks!

I get the same thing at the same speed 70+. Reminds me almost of a semi engine braking (though not nearly as loud). As soon as I touch the pedal it's gone again.

Very strange indeed.

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