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How does the 4A work?

Ser Arthur Dayne

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Correct, no 4WD (4H) on pavement. 4A can be run on dry pavement like any other AWD vehicle and lots of people do. Draw back is fuel mileage.
I thought that you could switch to 2H in Sport mode...no?
So thank you very much - I don't know if you can or not. Every time I switch to Sport Mode it says "4 Wheel Shift In Progress" and goes to 4A.
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MNbronco

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I would verify the IWE (integrated wheel ends) are working properly, in 4A the IWE engage
 

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So thank you very much - I don't know if you can or not. Every time I switch to Sport Mode it says "4 Wheel Shift In Progress" and goes to 4A.
I can confirm you can go into 2H in sport mode, you just have to press the 2H button every time you use sport mode
 

kyfigfam

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I get a slight vibration/suspension noise when in 2H and accelerate with any authority. It is NOT present when I'm in 4A. I have used 4A in heavier rains or gravel roads; noticeable difference. My assumption is that it is the soft Goodyears trying to grip the pavement.
 
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You are correct. In 2H, it will never engage anything but the rear wheels.
In 4A, 4 wheel drive is engaged when low traction condition is detected using clutches inside of the transfer case.
I am not sure how well the 4A system works in the Bronco yet, but when I monitor the power distribution screen when in 4A, it shows equal power to all 4 wheels all the time...
I also have a drive train noise when in 4A or 4H, noticeable when accelerating and goes away when you let of the gas/coasting. This is similar to my F-150, so I just assumed it was normal? Maybe its not?
Yea I get a chatter/ vibration. I didn't notice it until after I installed the lift.
 
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In 4A and accelerating (even slight) you will likely have some power going through the transfer case and driving the front axle.

The most likely cause for the vibration in this case is going to be the front driveshaft, when the lift was installed, was care taken to set the pinion angle properly for the new height?
That would make sense. The lift kit I installed did not come with a diff drop. I am almost positive what I'm feeling is due to the angle of the front axles. I have been looking for a diff drop solution but cant seem to find a company that makes one.
 
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Did the lift include a diff drop?
No it did not. I cant seem to find a company that makes one. The company that designed the lift said they are not sure why I'm feeling the vibration chatter. Im almost positive its because of the angles of the front CV.
 
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If you put it in 4H and accelerate, do you get the same driveline vibration? (You can use 4H on drive pavement for testing this but just keep it generally in a straight line...meaning no sharp turns right or left or you'll feel the front binding)
Yes I get the same vibration straight line, the vibration will go away once I click 2H.
 
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I get a slight vibration/suspension noise when in 2H and accelerate with any authority. It is NOT present when I'm in 4A. I have used 4A in heavier rains or gravel roads; noticeable difference. My assumption is that it is the soft Goodyears trying to grip the pavement.
Thats strange. Complete opposite of mine. Mine is definitely driveline.
 

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That would make sense. The lift kit I installed did not come with a diff drop. I am almost positive what I'm feeling is due to the angle of the front axles. I have been looking for a diff drop solution but cant seem to find a company that makes one.
OK, Yeah, if no Diff Drop, it's not gonna be the Pinion Angle, but the axles are a good possibility, However if you're saying putting it into 4 High stops the noise, I'm kinda thinking it's not that either.

Have you actually tried light acceleration while in 4 High? or just pulled it back into 4 High?

How high is the lift kit you installed?

Rough Country makes a Lift kit (5") with a diff drop for Bronco's, Not sure of anyone else who does, and I'll reserve judgement on the RC kit for now....
 
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OK, Yeah, if no Diff Drop, it's not gonna be the Pinion Angle, but the axles are a good possibility, However if you're saying putting it into 4 High stops the noise, I'm kinda thinking it's not that either.

Have you actually tried light acceleration while in 4 High? or just pulled it back into 4 High?

How high is the lift kit you installed?

Rough Country makes a Lift kit (5") with a diff drop for Bronco's, Not sure of anyone else who does, and I'll reserve judgement on the RC kit for now....
4A causes the noise/vibration 2H it will not have any issue. I installed a 3'' kit (not from RC). Light acceleration or hard acceleration the chatter comes and goes at different MPH Im pretty sure its the axles at their limits. Im having a "certified" tech look at it on Monday just (per the lift companys request, even tho I'm a mechanic as well and know I installed it correctly).
 

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OK, Yeah, if no Diff Drop, it's not gonna be the Pinion Angle, but the axles are a good possibility, However if you're saying putting it into 4 High stops the noise, I'm kinda thinking it's not that either.

Have you actually tried light acceleration while in 4 High? or just pulled it back into 4 High?

How high is the lift kit you installed?

Rough Country makes a Lift kit (5") with a diff drop for Bronco's, Not sure of anyone else who does, and I'll reserve judgement on the RC kit for now....
Rough Country's 3.5 inch kit also includes the differential drop, but it is only a 0.38" drop. They are splitting up all of their options, spacer lift + spring preload + baby differential drop, in order to keep the CV angle from binding at droop.

I doubt that a 3/8" drop will help this situation (RC will sell this individually if you call them - about $120 if I recall), and I do not know anyone who sells a substantial drop. There is someone on here who fabricated his own 1.5" drop - but it was a lot of work.
 

mike8675309

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AWD in the Bronco's transfer case results in power being sent to the front and rear with the center differential unlocked. When you are in full-time 4wd, generally the center differential is locked. That is not how all AWD systems work, particularly those in cars or small SUVs.

In 2wd, power is sent to only one end of the vehicle.
 

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4A causes the noise/vibration 2H it will not have any issue. I installed a 3'' kit (not from RC). Light acceleration or hard acceleration the chatter comes and goes at different MPH Im pretty sure its the axles at their limits. Im having a "certified" tech look at it on Monday just (per the lift companys request, even tho I'm a mechanic as well and know I installed it correctly).
OK, Yup, three inches is right at the edge of the most the axle shafts can take from everything I hear.
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