A Vibration & Hum when only in 4A and at a specific speed.

[Jugg2Driver]

Some quick details on my Expo.
2021 Expo Platinum Max, 50k miles, new Michelin tires.
95% of my driving is done in 2H, I only switch to 4A when conditions warrant it.

I noticed a vibration and hum yesterday that has never occurred before and it's very specific. The best way to describe the vibration & hum is like you're driving over some recently milled concrete.

The vibration and hum happen as a very specific speed range of 35-30mph, happens only in 4A and only when slowing down (coasting or braking). If I switch to 2H while the V&H is occurring it will immediately cease making that V&H. My assumption is a diff or axle shaft. I would think if it is wheel or tire related than the circumstances when it occurs wouldn't be so very specific. I also don't believe it is a vacuum hub issues as there isn't any significant noise that can be heard from the outside nor does it make that specific grinding noise that my 2015 F150 did when it had those hub issues. I'll schedule a service visit soon, but I'm curious if anyone else has had or heard of a similar issue. A quick search of the site didn't seem to turn up anything quite this specific.

Thanks in advance

 

[BMW2FORD]

Yep, very common hub issue (IWE) or lack of sufficient vacuum to the hub if you have the older vacuum system since sometimes the check valve on the firewall goes bad and lets the IWEs fall to a sort of locked / unlocked in between position and they make that noise due to partial engagement. I did a post here on the updated IWE vacuum check valve. That might be an easy fix rather than going to the dealer if your truck has that system since I also hate to say it but what Ford is doing now is simply disconnecting the vacuum system so you hubs are always engaged and there’s even a service bulletin telling the techs to do this rather than fix it. Kills me that you have a cool system and they choose to just eliminate it rather than fix it!!!

 

[BMW2FORD]

Integrated front wheel hub 4wd grinding $20 upgrade. “Save your front wheel hubs easily”

So I took my car to the dealer and asked him if this can be changed in my 22 timberline. Unfortunately they say the vacuum is controlled through the TCM and no such valve exists in this model. Wonder if that is any true. If so how can the problem be fixed because I still get the noise...

www.expeditionforum.com

 

[BMW2FORD]

Here’s the post about the info informing the dealers to eliminate the system.

TSB 24-2188 - 2003-2020 Expedition/Navigator + F-150 - 4WD - Grinding/Clicking/Ratcheting Noise From Front Wheel Area July 23, 2024

TSB 24-2188 4WD Grinding/Clicking/Ratcheting Noise From Front Wheel Area - July 23, 2024 This bulletin supersedes 22-2219. Reason for update: revised Part List and Service Procedure to clarify applicable steps by vehicle application Model: Ford 2003-2020 Expedition 4WD 2006-2020 F-150...

www.expeditionforum.com

 

[Jugg2Driver]

Thanks. I've looked through both of those threads and the issues don't quite line up to what I'm experiencing. At least by description.