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Why Front Axle Disconnect (FAD) on some and not others?

dgorsett

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Browsing the axle availability chart (the most valuable thing from the build sheets) I noticed FAD is on some combos and not others. It's obvious that those with Advanced 4x4 don't have it (Sasquatch and select others) which makes sense. But some, specifically those with 4.27 gears (optioned BB and OBX) don't have it either, with regular 4x4. I'm shopping BB with rear 4.27 locker with open 4.27 front, it has no FAD. I'm 50/50 on FAD anyway, Good: wear and tear and mpg Bad: reliability issues.

Does anyone know what Ford's logic on this is from an engineering, cost or ease of build standpoint
Ford Bronco Why Front Axle Disconnect (FAD) on some and not others? 2021 Bronco order guide 31
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Glitch, in the B&P; 4.27 only shows only as an option for the Outer Banks when you click on information. Found a couple other nonsense things in the pdf. as well. I would not bother looking for answers until time to order. (the B&P could be wrong as well, but... when Ford sourced info shows two things, I am thinking it is a third completely different thing.)
 

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It looks like the lack of front axle disconnect ties to the option combos containing the Advanced 4x4 transfer case.
 
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dgorsett

dgorsett

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It looks like the lack of front axle disconnect ties to the option combos containing the Advanced 4x4 transfer case.
Correct, except for the exceptions I noted with the BB and OBX with 4.27's, Here's the whole axle availability sheet with footnotes.

Ford Bronco Why Front Axle Disconnect (FAD) on some and not others? 2021-Bronco-Order-Guide-31
 

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It looks like the lack of front axle disconnect ties to the option combos containing the Advanced 4x4 transfer case.
It's also tied to not having the locking differential.


For the automatic 4x4, the system is always engaging and disengaging. This can cause substantial wear in the axle disconnect mechanism. Also, if the mechanism fails, the resulting free spinning of the axle shafts can tear up the guts of the transfer case that manage the torque bias.

For the locking differential, the axle disconnect is a weak point and the added stress of a locked differential can cause premature failure.
 

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dgorsett

dgorsett

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It's also tied to not having the locking differential.


For the automatic 4x4, the system is always engaging and disengaging. This can cause substantial wear in the axle disconnect mechanism. Also, if the mechanism fails, the resulting free spinning of the axle shafts can tear up the guts of the transfer case that manage the torque bias.

For the locking differential, the axle disconnect is a weak point and the added stress of a locked differential can cause premature failure.
All true! There is still the anomaly of the 4.27 non locking, non automatic 4x4 systems on certain BB and OBX's. Like I say I'm six of one half a dozen of the other, but the reliability of a non FAD axle will be fine.
 

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Has anybody seen any technical information about the FAD or pics of it? Is it at the wheel ends, outside the differential, or inside the differential? I haven't noticed it but I haven't really been looking for it, either.
 
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dgorsett

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I'd like to revive this thread, even though I might be the only one interested :unsure:

The real reason I want to know, is in both cases BD and OBX 4.27 w/o FAD they are available with stand alone Adv 4x4. The exception is BB 4.27. It shows no FAD, but also ADV 4x4 is not shown available as a stand alone w/o Sas. I'm just triple checking to see if there is a way to get Adv 4x4 on a BB without Sasquatch before I can't modify my order.

A month ago my dealer tried to add it in WEBDO and couldn't w/o Sas. I'm just checking with the experts to see if there is a work around.
 

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Has anybody seen any technical information about the FAD or pics of it? Is it at the wheel ends, outside the differential, or inside the differential? I haven't noticed it but I haven't really been looking for it, either.
I assume it is within the Transfer case, others please correct me if that assumption is incorrect. Here are some pics and a a number of likes to numerous chassis photos to see different elements.

https://www.bronco6g.com/forum/thre...ansmission-driveshaft-differential-more.1815/

https://www.bronco6g.com/forum/thre...s-frame-suspension-axles-hubs-engine-️.10813/

https://www.bronco6g.com/forum/threads/labeled-front-suspension-drivetrain-components.6345/

https://www.bronco6g.com/forum/thre...-east-post-them-here.6360/page-14#post-232914

20200907_190348-jpg.jpg

bronco_parts_20-jpg.jpg
 
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dgorsett

dgorsett

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I believe it's actually at each wheel/hub. Vacuum operated as in other Fords. It acts like old fashioned hubs just automatically when transfer case is engaged. Ford also calls it IWE (Individual wheel engagement). All vehicles with the Advanced Transfer case don't have it as the transfer case engages automatically and perhaps frequently which might prove troublesome. The anomaly is the BB part time 4x4 w/4.27 axles, it is shown in the axle selection chart as also not having FAD/IWE.

I looked through the photos you referenced and non had a good angle and all the plumbing wasn't installed yet, plus I may not know exactly what I'm looking for1

I was in Moab and examined the bare Sasquatch chassis, but forgot to look at the hubs!...duh.
 

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disco sway is to get you to upgrade.

Id order the base with the sasquatch if it was part of the package...but its not so I guess I am going BADLANDS
 

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What you're describing sounds more like a 2WD mode rather than a front axle disconnect. I assumed they were talking about something to disconnect the front wheels from the drivetrain but with certain models not getting the "feature" I am not really sure what to think.

For what it's worth, I just looked at my coworker's 2018 F150 which has the 4A mode and his truck has vacuum disconnects at the front hubs.
 

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What you're describing sounds more like a 2WD mode rather than a front axle disconnect. I assumed they were talking about something to disconnect the front wheels from the drivetrain but with certain models not getting the "feature" I am not really sure what to think.

For what it's worth, I just looked at my coworker's 2018 F150 which has the 4A mode and his truck has vacuum disconnects at the front hubs.
The front differential looks like it has a vacuum line to it, could that be it? I looked for one on the real differental but could not find one in the pics.

bronco_parts_20-jpg-jpg.jpg
 

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I believe it's actually at each wheel/hub. Vacuum operated as in other Fords. It acts like old fashioned hubs just automatically when transfer case is engaged. Ford also calls it IWE (Individual wheel engagement). All vehicles with the Advanced Transfer case don't have it as the transfer case engages automatically and perhaps frequently which might prove troublesome. The anomaly is the BB part time 4x4 w/4.27 axles, it is shown in the axle selection chart as also not having FAD/IWE.

I looked through the photos you referenced and non had a good angle and all the plumbing wasn't installed yet, plus I may not know exactly what I'm looking for1

I was in Moab and examined the bare Sasquatch chassis, but forgot to look at the hubs!...duh.
I've never seen IWE expanded as "Individual Wheel Engagement," but it certainly sounds better than "Integrated Wheel Ends"! An acronym only an automaker could come up with...
 
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