4A issues. ford says this is normal?

[broncobase1]

4A mode has to figure out if the difference between a parking maneuver and situations that require 4WD.

Without regard for how Ford has decided to classify 4A as OK for all conditions, it really shouldn't be used on exclusively dry surfaces. If you're concerned about slip, traction control is always running in the background under normal driving and will take care of most of the reasons for a slip. It has been my understanding since 4A was introduced, the intended use was mainly for snowy/icy/slippery road conditions, as a more desirable option to running 4x4 on highway conditions.

I have not bothered looking at the WSM to see exactly what conditions are required to activate the 4A strategy but right angle-ish turns where the outside wheels are moving much faster than the inside, tire circumference variations and the obvious slick conditions are usually enough to do it. Feel free to argue with me but I see no reason to run 4A on dry pavement under "normal" conditions. There are too many variables that can cause it to engage when not needed and put undue stress on the CVs and other part time components. There is absolutely no benefit to use it for daily driving. Like I said, it's what you use when you might need 4x4 assist but driving conditions are outside of the 4x4 limits (highway speeds).

There's a 90%+ chance that most unintended 4A activations fall within designed operating parameters. The few that fall outside are due to diagnosable issues like tire size or a speed sensor.

I agree with you on this one. Without being an expert on 4A I'm not saying there isn't anything wrong, but it has to decide when and when not to engage 4WD and this decision can be tricky in a sharp turn. I don't have 4A, but there has been a few times when I accidently had it in 4H and it makes it difficult to make a tight turn on dry pavement, not simply a matter of some tire chirping. OP try making the same maneuver in straight 4H mode and see what the difference is.

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[adam1991]

but it has to decide when and when not to engage 4WD and this decision can be tricky in a sharp turn.

not at all.

My broken transfer case caused shudder in a u-turn on dry pavement in the August sun on my 3 day old OBX.

The new transfer case they replaced it with a week later, at Ford's direction, does no such thing.

Stop making excuses for Ford's badly built 4A transfer cases.

The good news is, 2H/4H/4L are unaffected by this. So, worst case, you just pretend you don't have 4A.

 

[Ducati1098]

4A mode has to figure out if the difference between a parking maneuver and situations that require 4WD.

I agree with you on this one. Without being an expert on 4A I'm not saying there isn't anything wrong, but it has to decide when and when not to engage 4WD and this decision can be tricky in a sharp turn. I don't have 4A, but there has been a few times when I accidently had it in 4H and it makes it difficult to make a tight turn on dry pavement, not simply a matter of some tire chirping. OP try making the same maneuver in straight 4H mode and see what the difference is.

It’s not really tricky at all. Low speed turns and low throttle position the clutch should be disengaged. It knows steering wheel position and throttle position and it can easily decide when to disengage the clutch.

The fact that multiple people have had this issue resolved by getting their transfer case replaced proves that the binding shouldn’t be happening.

 

[twinturbo4vGT]

Without regard for how Ford has decided to classify 4A as OK for all conditions, it really shouldn't be used on exclusively dry surfaces. If you're concerned about slip, traction control is always running in the background under normal driving and will take care of most of the reasons for a slip. It has been my understanding since 4A was introduced, the intended use was mainly for snowy/icy/slippery road conditions, as a more desirable option to running 4x4 on highway conditions.

I have not bothered looking at the WSM to see exactly what conditions are required to activate the 4A strategy but right angle-ish turns where the outside wheels are moving much faster than the inside, tire circumference variations and the obvious slick conditions are usually enough to do it. Feel free to argue with me but I see no reason to run 4A on dry pavement under "normal" conditions. There are too many variables that can cause it to engage when not needed and put undue stress on the CVs and other part time components. There is absolutely no benefit to use it for daily driving. Like I said, it's what you use when you might need 4x4 assist but driving conditions are outside of the 4x4 limits (highway speeds).

There's a 90%+ chance that most unintended 4A activations fall within designed operating parameters. The few that fall outside are due to diagnosable issues like tire size or a speed sensor.

The problem with your assessment is I'm not doing anything you're describing. It's in slippery GOAT mode which goes into 4A, making a 2-3mph without my foot on the gas turn into a parking spot while it was raining. The wheels should not be chirping like that...

 

[killaz05]

unless it is full on binding, I wouldn't worry too much about it. put it in 4H and I bet you notice a huge difference. When in 4A, part of the front drive system is engaged in case it needs to send power to the front almost instantly so I would expect some more steering effort etc. It doesn't just fully disengage the front when it is only sending power to the rear.

If you are worried about whether the 4A is working, you can see the power distribution on one of the dash screens. The front gets power a good amount of time but when cruising or a very soft acceleration, the front won't get power. Watch the power distribution and how quickly it will send power to the front wheels, and it makes sense the front still has some engagement. Cruise till you see it is only sending power to the rear and then accelerate at a decent pace (doesn't need to be floored).

 

[twinturbo4vGT]

https://www.bronco6g.com/forum/threads/updated-check-4x4-warning-alert-4a.32371/

You have a bad transfer case.

and therefore, as a practical matter, you don't have 4A.

Thats what I figured. I'm not stupid this truck is NOT supposed to bind up on a 3mph turn into a parking spot. Also even driving in a straight line I'm getting power to all 4 wheels like the exact same issue you were having.

 

[twinturbo4vGT]

unless it is full on binding, I wouldn't worry too much about it. put it in 4H and I bet you notice a huge difference. When in 4A, part of the front drive system is engaged in case it needs to send power to the front almost instantly so I would expect some more steering effort etc. It doesn't just fully disengage the front when it is only sending power to the rear.

If you are worried about whether the 4A is working, you can see the power distribution on one of the dash screens. The front gets power a good amount of time but when cruising or a very soft acceleration, the front won't get power. Watch the power distribution and how quickly it will send power to the front wheels, and it makes sense the front still has some engagement. Cruise till you see it is only sending power to the rear and then accelerate at a decent pace (doesn't need to be floored).

Did exactly that. 4 wheel power distribution all the time...

 

[adam1991]

It's in slippery GOAT mode which goes into 4A, making a 2-3mph without my foot on the gas turn into a parking spot while it was raining. The wheels should not be chirping like that...

100%

And Sport mode engages 4A automatically, and Sport mode is intended for dry pavement...I don't get where people come here trying to make excuses for the malbehavior of Ford's advanced transfer case. No, that's not normal and no, it's not supposed to do that.

 

[Ducati1098]

It doesn't just fully disengage the front when it is only sending power to the rear.

Yes it does. The clutch duty cycle goes to 0% just as it would be if you were in 2H instead of 4A

 

[twinturbo4vGT]

Yes it does. The clutch duty cycle goes to 0% just as it would be if you were in 2H instead of 4A

Exactly. Way too many people in here are giving wrong information. Mine is acting like it's in 4H all the time.

 

[joes bronco]

Sure glad my bronco doesn't have the all-wheel drive one less issue to deal with LOL.

 

[Techun]

I understand your point, but 4A works fine most of the time on all surfaces. I am approaching the point where I am confident that 4A can tolerate full time daily use.

There is some chatter/drag at low speed high steering angles that can be induced, but it doesn't appear to be a problem from the standpoint of reliability (n of 2). The easiest answer is to keep it in 2H if you are not happy with the low speed behavior.

Yeah but...why use 4a on dry surfaces

 

[twinturbo4vGT]

Yeah but...why use 4a on dry surfaces

Because it's what is used in sport mode for dry surfaces...

 

[adam1991]

Sure glad my bronco doesn't have the all-wheel drive one less issue to deal with LOL.

your Bronco doesn't have all-wheel drive? Oh, you mean Ford's Advanced 4x4 with the different transfer case.

 

[adam1991]

Yeah but...why use 4a on dry surfaces

please direct that question to Ford engineers, who:

1. programmed it to engage in Sport mode
2. have gone on record saying "it's meant to be left on for the life of the vehicle"

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