So 4A is not what I had thought...

[telenerd]

I just wasted 10 minutes reading this thread.

Happy New Years everyone!

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[Bdisco]

 

[Mikesmallcrawler21]

Over the last couple years there has been several discussions about 4A, along with all the "rules" about using 4x4 in high traction environments (like the street).

I've even contributed to multiple threats about 4A where the thought process was that it's in two-wheel drive unless it's senses slippage and then it kicks into 4 wheel drive.

This is not the case and Ford has seemed to have reinvented physics

All of us that have SPORT mode know that 4A engages with this GOAT and it is specifically designed for the street. Now that goes against the "No 4x4 on street" rule. However with the mentality that the 4A/4H doesn't kick in until it needs to, it should not be an issue.

Well I've been playing around with 4A and watching the "power distribution" and a bunch of us, including myself, we're wrong with our assumptions.

4A basically has the vehicle in 4x4 mode pretty much the entire time. There are some inconsistencies, but the only time that I've seen it NOT applying power to all wheels is when off the throttle, or I think, if you have the steering significantly turned BEFORE applying throttle.

To give you some examples, going 75 mph down the freeway and giving it some throttle = 4 wheel drive

Throttling while going through twisty turns on a mountain road = 4 wheel drive.

To me the scariest.... Doing a U-turn at a light (which requires throttle) = 4 wheel drive.

Like I said, there have been a couple of situations when I was testing, and if I turn the steering wheel significantly Before applying the throttle, it seems = 2 wheel drive.

I don't get me wrong, I love the feel of basically AWD... It's been storming (rain) all week where I live, and in 4A, the Bronco has been planted and not a single wheel slip.

I just hope Ford design this correctly and taking windy roads in sports mode isn't going to break something.

Push the 2wd and it will stay in sport mode, but only.2 wd.... its with any that have ADV 4X4

 

[Jamesorriv]

Here is a good tear down from a mechanic on the Bronco transfer case (and is very anti-4A).


(skip to 16 mins to see how the clutch is activated). I think towing with the transfer case in 4A is the reason for the clutch replacement.

Also here is animation from Borg-Warner on how the transfer case works:


Watching the two vids suggests that to get any sort of torque bias other than no-connect/lock is to operate the clutch in the slipping region. Now maybe Ford programming does not do this, in which case they are just engaging/dis-engaging the front axle based on inputs (throttle, steer angle, ABS, etc), but not doing any kind of torque-bias like other AWD systems.

Btw the clutch is a wet-clutch so can handle the "slipping region" better than a dry clutch.

 

[markpilip]

Here is a good tear down from a mechanic on the Bronco transfer case (and is very anti-4A).


(skip to 16 mins to see how the clutch is activated). I think towing with the transfer case in 4A is the reason for the clutch replacement.

Also here is animation from Borg-Warner on how the transfer case works:


Watching the two vids suggests that to get any sort of torque bias other than no-connect/lock is to operate the clutch in the slipping region. Now maybe Ford programming does not do this, in which case they are just engaging/dis-engaging the front axle based on inputs (throttle, steer angle, ABS, etc), but not doing any kind of torque-bias like other AWD systems.

Btw the clutch is a wet-clutch so can handle the "slipping region" better than a dry clutch.

We've seen this guy before. If he's a mechanic, then I'm an astronaut. If you figure out which dealership he works for, let us know so we can stay far, far away. I don't want this guy anywhere near my Bronco.

 

[BroncocnorB]

My dad told me I should be an astronaut. I’m good at taking up space. Happy New Year!

 

[Jkoren12345]

Why not just put it back in 2H? That’s how I use Sport.

100% agree. Sport mode in 2H is the way to go-great power, response and feel. It's my favorite combo....

 

[mpeugeot]

How about some real world Bronco data, I have driven my 2021 Bronco over 55,000 miles nearly exclusively in 4A sport mode. It is not an issue and I don't baby it.

 

[Ducati1098]

We've seen this guy before. If he's a mechanic, then I'm an astronaut. If you figure out which dealership he works for, let us know so we can stay far, far away. I don't want this guy anywhere near my Bronco.

Dundee Ford in Illinois. Guy is an absolute hack.

 

[Mike D]

The saying is “ignorance is bliss”. I’m glad I have no mechanical aptitude and no idea how this sh*t is supposed to work. I turn the knob, my bronco seems to drive great, and I’m done.

 

[ForFoxSake]

God damn I wasted 10 minutes reading this thread and nothing had told me whats right or wrong.

I've been driving in 4A all winter so far.....it's much safer then 2H.

Am I doing something wrong? I've referred to the manual....I don't get what the issue is? With the guages it seems like its almost like a AWD system.

4A all the time, yes or no?

 

[FLSTFI Dave]

Over the last couple years there has been several discussions about 4A, along with all the "rules" about using 4x4 in high traction environments (like the street).

I've even contributed to multiple threats about 4A where the thought process was that it's in two-wheel drive unless it's senses slippage and then it kicks into 4 wheel drive.

This is not the case and Ford has seemed to have reinvented physics

All of us that have SPORT mode know that 4A engages with this GOAT and it is specifically designed for the street. Now that goes against the "No 4x4 on street" rule. However with the mentality that the 4A/4H doesn't kick in until it needs to, it should not be an issue.

I will have to watch how 4A operates on this. On my F-150, you put in it 4A and it only engaged the front if slippage was detected. I thought that was how this operated.

This is from the owners manual, and leads me to believe it operates like my F-150

HOW DOES FOUR-WHEEL DRIVE WORK - ADVANCED 4X4

WITH 4A MODE
Advanced 4x4 With Automatic OnDemand Engagement (If Equipped)

This system monitors various vehicle sensory inputs to provide an increased level of performance. This system offers the driver two-wheel drive high, four-wheel drive auto, four-wheel drive high, and four-wheel drive low as available modes of operation. When you select four-wheel drive auto, the system continuously varies power to the front wheels for optimum performance for all on-road conditions.

Interesting on the Wildtrak that Sport also engages 4A. My Bronco Raptor, Sport does not engage 4A. It stays in 2H on the goat dial and on the power distribution screen. I can elect 4A in sport mode if I want to.

 

[Ground_zero298]

4h = power is sent to front wheels all the time.
4a = push skinny pedal, power is transferred to front wheels. Take foot of pedal, power is taken away from front. That’s the dry pavement explanation.

It pretty much equates to = lay into pedal in 4a and it just became 4h.

Only vehicles I know that have issues of using 4a all the time are gm big bodies with 6.2’s in them. Last 3 started showing signs around 30k miles. But them 6.2’s are beastly on the low end for torque.

We got a 2019 ct6 v tt. Close to 700 horse, awd. Goes to a real race track all the time, not that 1/4 mile bs. Have boiled the brake fluid over 2 times, over heated the brake system 3 times. Have never had a issue with the drivetrain. That car is also capable of burning all 4 at 60mph.

 

[da_jokker]

Wow, a lot of responses.

I'm glad to hear there are lots of people that have been running 4A with no issues. My post wasn't to focus on how 4A works, just more so on the fact of whether it's okay to use on dry pavement.

Maybe I should have included this in my original post, but here is the dilemma...

Sports mode = 4A and obviously okay on dry pavement.

Slippery mode = 4A And the owner's manual warns about potential damage to the 4x4 system on pavement.


I guess that is my question? I've been using slippery mode with all these torrential downpours.... But when I actually bothered to look it up in the owner's manual, it makes it sound like It should not be used....

SLIPPERY - ADVANCED 4X4 WITH
4A MODE

For less than ideal road
conditions, this mode can be
used for crossing terrain where
a firm surface is covered with loose or
slippery material, such as snow or ice....

Note: When using Slippery mode on
dry/hard pavement, your vehicle could
experience vibration, driveline bind up,
damage and potential excessive tire and
vehicle wear.


So why can sports mode use 4A on pavement, but slippery mode can't ?

 

[da_jokker]

You are misreading the displays for sure. 4A is in fact just like any other all wheel drive vehicle like my X4 rear wheel drive always and only engages front when slippage occurs. These are not intelligent like Subaru or Honda.

That was my point, this is not true. In fact it's the opposite. In 4A the Front is always engaged and only disengages in certain situations (like off throttle and hopefully binding)

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