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

[XirallicBolts]

I assumed it was like the soft-AWD on the crossovers -- during initial acceleration it'll be 4x4 and tapers off once you reach speed, reengaging if slip is detected. My Silverado is similar, though it's light-duty with a single-speed transfer case. 2Hi is 2wd, 4hi is 4x4 with locked rear, 4A is like our 4A with unlocked rear.

You think your power distribution screen is a lie? For whatever reason they just could not figure out how to get the screen working properly on Taurus/Flex so they disabled it entirely. Something about how the Explorer IPC was made by a different company and despite all three using identical drivetrains and sensors, the Taurus/Flex IPC manufacturer couldn't get the speed sensor math to work on the IPC.

Let me just add fuel to the fire here. There have been several posts already that are 100% correct, that is all I have to say about that. What I would like to point out is there is only 2 quarts of fluid in the transfer case and if one uses 4A a lot I would suggest changing out the fluid often. Not only from heat build up but the materials from the clutch wear. There is no filter in the transfer case like in trans or engine.

I would say at least every 25-30K and/or at the end of winter conditions.

Sounds just like the Flex/Taurus/Explorer, lmao. It only has 0.5L of fluid, no airflow, no external cooling, and surrounded by the engine/transmission/catalytic converter. Ford claims the fluid is good for life and they're lying through their teeth the whole time. 30k or after winter. Hopefully it's easier to find a 4x4 shop that'll change the Bronco's fluids because half the shops around here tell me to go to to the dealer. Even the police versions lack external cooling and just add a temperature sensor to let them know when the fluid is cooked.

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[PrincipalD]

Okay. I did it. I read the owners manual. Here is a quote form page 182:

“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.”

I 4A is fine for everyday use as that is “all on-road conditions” per the last sentence.

I hereby announce this thread closed so we can go back to the real issues of no cup holders in the back of four doors, chip shortages, and whether or not I have to remove crashbars with a 33.5” tire upgrade.

*** Disclaimer - I am not a mechanic nor could I do most anything on my Bronco without this forum or YouTube videos. So, yes, I am an expert.

 

[BigMeatsBronco]

Those were not AWD but 4WD. But as a caveat my Cherokees supplied power Continuously through the mid mpqunt tqranasfer case and the shifting into getting power to front axle was an electric solenoid shifting a gear inside the axle. The full time power to the transfer case maodel was what starting in the 70s allowed shifting I to 4wd at speed and not a crawl

Alot changed between the 70s and 80s. Center diffs in the transfer case have been around a long time in many vehicles....again these are prehistoric compared to the broncos system.

 

[BigMeatsBronco]

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.

Sorta, maybe, but these bar gauge displays are quite accurate and have been used in isuzu with nearly identical BG TC since 1998...borg Warners design is programmed so that when you apply throttle the front tires instantly receive more torque ( and the bar Guage shows this accurately)....before the REAR tires get a chance to slip. Additionally, there are sensors on the front and rear driveline, inside the t-case that allow the computer to detect both tire slip and also the allowable rate of driveline rotation mismatch by calculating steering angle input. Basically it knows the turning circle of each tire on the vehicle and the number of rotations each will make at any given turning radius. This allows the system to predict and prevent
Driveline bind when in a tight turn on dry pavement, it sees the steering
Angle, makes calculations, and adjusts or releases the clutch preasure BEFORE bind or tire slip occurs! Seems intelligent enough to me. The system also uses wheel speed sensors as well to read the tires rotation individually and compares it with the steering input angle to detect the vehicle sliding sideways or more than one tire slipping. Older systems don't do any of this.

 

[rtazz17]

Alot changed between the 70s and 80s. Center diffs in the transfer case have been around a long time in many vehicles....again these are prehistoric compared to the broncos system.

Yup,usually the more electronics involved the more problems that will occur. Fingers crossed this wont be the issue. Im all for mechanical everything or at least mechanical back up. Like the front hubs,no mechanical option to manually turn them. Once the electronics fail,you lost ability to put in or out of 4wd.

 

[JohnnyBronco]

This doesn't surprise me, but I am wondering why it is delivering power to all wheels is a concern because it shouldn't.

The descriptions that 4A was just a means to automatically engage 4H when there was wheel slip never made sense. It is al all wheel drive system (AWD).

I think it all gets messed up by Ford and others trying to differentiate AWD from 4WD to lay people who really don't understand why conventional 4WD systems can't be run on dry pavement. So they use analogies they consider good enough for the lay person that are technically inaccurate.

So there are oversimplifications like the "its like 2WD but all 4WD when you need it" or oversophistications (like that word I made up) that describe it as some magic system that detects slip at a wheel and directs power to it.

Then people who know how cars work try and take that language literally.

If you don't know what a differential does between your drive shaft and wheel axles to allow the wheels to turn at different rates stop here.

If you know what a differential is, you probably know that 4WD is no bueno on dry pavement because the basic transfer case does not allow front and rear drive shafts to turn at different speeds. So it binds up when turning because front and rear axles need to be at different speeds just like the right side wheels are going to be different than left side wheels. That trying to turn on dry pavement would be much like trying to do so with locker engaged at the differential.

So to change 4WD to an AWD system it just needs to allow the two drive shafts to rotate at different speeds. I am not sure how most do this. One method would be the equivalent of a differential at the transfer case. Down side would be one wheel slipping in 4A could result in getting stuck unless that diff in the transfer case was limited slip.

In what I described above going between 4A to 4H would be the equivalent of locking that differential in the transfer case.

I don't know that is how it is done. One could make a system where all power goes to the lower speed drive shaft while the faster "free wheels" sort of like a bicycle wheel when you don't pedal. In any case going from 4A to 4H just goes from allowing the drive shafts run at different speeds to them being locked to the same speed.

The way any open diff works is power is transmitted to the position with the least resistance or traction. Hence the need sometimes to lock or resist the diff to get power to the wheel that actually needs it. Traction Control in most new vehicles applies the brakes to the position with least traction¹⁸

Somewhat on topic- my understanding is that you can shift in and out of 2H to 4A on the fly.
Has anyone experienced problems regarding speed or road conditions ?

You won't even notice the difference unless you look at the power distribution display or the mode indicator.

But as soon as you sect Sport you will be back in 4A. Why Sport is disabled in 2H is a question that will never have a decent answer other than they (Ford) do not want anyone leaving a pavement stripe (just one unless you can lock your rear diff in 2H or transition from reverse into forward at full throttle)

 

[BigMeatsBronco]

Yup,usually the more electronics involved the more problems that will occur. Fingers crossed this wont be the issue. Im all for mechanical everything or at least mechanical back up. Like the front hubs,no mechanical option to manually turn them. Once the electronics fail,you lost ability to put in or out of 4wd.

Huh? the 6g uses drive flanges not hubs, NOTHING to fail there!!! lesser models do have front axle disconnect tho....maybe that's what your referring to?
The Braptor does have vacuum operated axle disconnects on BOTH CVs. This is the most stupid setup ever!!! Here's a picture.

 

[Christoph94]

‘22 Badlands, and in 4A …I can feel that this drives much more like my ‘87 Ranger in 4WD, compared to both my ‘12 F150 and ‘16 Navigator in 4A. I’ve switched between 4H and 4A and it feels identical to each other, can feel it in the steering wheel. I only brought up the bar gauge after something didn’t feel right about this 4A, and gauge indicated what I was feeling. I will be taking it to the dealership for them to check out.
Love the Bronco overall, but 4A to this point has been my only disappointment.

 

[2112]

Sounds just like the Flex/Taurus/Explorer, lmao. It only has 0.5L of fluid, no airflow, no external cooling, and surrounded by the engine/transmission/catalytic converter. Ford claims the fluid is good for life and they're lying through their teeth the whole time. 30k or after winter. Hopefully it's easier to find a 4x4 shop that'll change the Bronco's fluids because half the shops around here tell me to go to to the dealer. Even the police versions lack external cooling and just add a temperature sensor to let them know when the fluid is cooked.

Is there a drain plug? Or does it take R&R to change fluids like my wife’s SS Camaro transmission?

 

[BigMeatsBronco]

But as soon as you sect Sport you will be back in 4A. Why Sport is disabled in 2H is a question that will never have a decent answer other than they (Ford) do not want anyone leaving a pavement stripe (just one unless you can lock your rear diff in 2H or transition from reverse into forward at full throttle)

This backwards...Sport is NOT disabled in 2WD, but instead 2WD is NOT default for Sport. Many of us can and do run sport and 2WD together.

 

[XirallicBolts]

Is there a drain plug? Or does it take R&R to change fluids like my wife’s SS Camaro transmission?

For the cars I mentioned, it depended on the year and equipment. If present, a vacuum pump could get the fluids out in place. Otherwise it was possible to drill a drain without removal.

I'd assume 100% of Broncos have a drain plug

 

[BigMeatsBronco]

We will have to disagree padawan.

Note: It is because of people like you that I never buy used.

If you think about it, it's almost identical in heat and wear that's added by changing from an open diff to a limited slip diff, ( in a normal rear axle) the amount of slippage is similar....virtually ZERO change in wear, heat or reliability. By your logic all the limited slip axles out there with 35k miles should be worn out junk by now.

 

[Shazamalingo]

I have seen 4A in Slippery mode is only giving power to all 4 wheels when accelerating, etc... It delivers power to the back 2 wheels once you are at speed.

 

[MrOzMan]

I was under the impression 4A was it was driving both axles all the time, but the transfer case acted as an unlocked center differential, allowing for slippage on corners etc.

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.

 

[mere44]

This is from the Ford workshop manual, explaining each operation. Follow these and perform diligent maintenance and everything will be fine.

No need to guess what does what unless that makes you feel better. j/k

Enjoy! and Happy New Year!


(2H) OPERATION

When the ATCM is in (2H), power is delivered to the rear wheels only. This mode is appropriate for normal on-road driving on dry pavement and provides the best fuel economy. Torque is passed through the transfer case to the rear driveshaft at a 1:1 ratio. In (2H):

• The ATCM sends a (2H) mode status to the AWD module via the GWM .
• The transfer case clutch is at or below the kiss point.
• The reduction sleeve connects the input shaft and output shaft
• (2H) will momentarily be displayed in the message center at key up and after a 4WD to (2H) shift.

(4A) OPERATION

When (4A) is selected on the ATCM , the 4WD system provides electronically controlled four-wheel drive with power delivered to all four wheels, as required, for increased traction. (4A) is appropriate for all on-road driving conditions, such as dry road surfaces, wet pavement, light snow or gravel. Shifts from (2H) or (4H) to (4A) can be made at any speed. In (4A):

• The ATCM sends a (4A) mode status to the AWD module via the GWM .
• The shift motor positions the ball ramp device at the clutch kiss point when driving conditions do not require 4WD.
• The shift motor positions the ball ramp device to apply the clutch when wheel slip is anticipated or detected.
• The reduction sleeve connects the input shaft and output shaft
• (4A) is displayed in the message center.

AUTOLOCK

If the system is in (4A) and AWD module detects driving conditions that require greater 4WD performance, the AWD module temporarily turns on (4H). The message center displays 4X4 TEMPORARILY LOCKED. The 4WD system automatically returns to (4A) after the system no longer detects these driving conditions. The message center will temporarily display 4X4 RESTORED.

POWERTRAIN TORQUE PROTECTION

If the system is in (4A) and AWD module detects excessive stress or high energy going through the clutch (clutch is slipping excessively while the system is commanding max clutch torque), the shift motor will release the clutch and message center indicates 4x4 TEMPORARILY DISABLED. When the system had the ability to cool off, 4x4 operation will be automatically restored. The message center will temporarily display 4X4 RESTORED.

(4H) OPERATION

(4H) provides electronically locked four-wheel drive power to both the front and rear wheels for use in off-road or winter conditions such as deep snow, sand or mud. This mode is not for use on dry pavement. Shifts from (2H) to (4H) can be made at any speed. In (4H):

• The ATCM sends a (4H) mode status to the AWD module via the GWM .
• The shift motor positions the ball ramp device to completely apply the clutch.
• The reduction sleeve connects the input shaft and output shaft
• (4H) is displayed in the message center.

(4L) OPERATION

(4L) provides electronically locked four-wheel drive power to both the front and rear wheels for use on low traction surfaces but does so with an additional gear reduction for increased torque multiplication. Intended only for off-road applications such as deep sand, steep grades or pulling heavy objects. (4L) does not engage when your vehicle is moving above 3 mph (5 km/h); this is normal and should be no reason for concern.

Shifts to and from (4L) can only be made below 3.1 mph (5 km/h) with the transmission in Neutral. When performing this shift, wait until the 4x4 Shift in Progress message disappears in the IPC before moving the selector lever back to Drive. If the vehicle speed or transmission range is not within parameters, the message center will indicate the necessary action needed to complete the shift. In (4L):

• The ATCM sends a (4L) mode status to the AWD module via the GWM .
• The shift motor positions the ball ramp device to completely apply the clutch.
• The shift motor positions the reduction sleeve connecting the planetary carrier and output shaft
• (4L) is displayed in the message center.

NEUTRAL OPERATION

For recreational towing (all 4 wheels on the ground) the transfer case should be placed in Neutral.
Refer to: Neutral Flat Tow Activation and Deactivation (307-07B Four-Wheel Drive Systems - Advanced 4x4 with 4A Mode, General Procedures).

• The IPC sends a Neutral mode status to the AWD module via the GWM .
• The shift motor positions the ball ramp device to completely apply the clutch.
• The shift motor positions the reduction sleeve to only engage the output shaft
• “Neutral Tow Enabled” is displayed in the message center.

G.O.A.T. Modes

NOTE: Not all G.O.A.T. modes are available in each trim level.

The vehicle is equipped with Goes Over Any-type of Terrain (G.O.A.T.) Modes that allows the driver to enhance the off-road performance of the vehicle by selecting the mode best suited to the terrain and driving conditions. Each mode changes a number of the vehicle parameters within the engine, transmission, traction control and 4WD systems.

Normal

• For everyday driving. This mode is the perfect balance of excitement, comfort and convenience. This is the default mode after each ignition cycle, the driveline settings remain the same prior to the ignition cycle.
• (2H) is the default four-wheel drive mode. All four-wheel drive modes are selectable when in normal mode.
• The front electronic locking differential, if equipped is available when in (4L).
• The rear electronic locking differential, if equipped is available.
• The stabilizer bar disconnect is available if (4H) or (4L) is selected.

Eco

• For efficient driving. This mode helps deliver maximum fuel efficiency and helps to increase driving range.
• (2H) is the default four-wheel drive mode. (4L) is not selectable in eco mode.
• The front electronic locking differential is not available in eco mode.
• The rear electronic locking differential is available.
• The stabilizer bar disconnect is not available in eco mode.

Sport

• For sporty driving with improved performance handling and response. This mode increases accelerator pedal response and provides a sportier steering feel. The powertrain system holds onto lower gears longer, helping your vehicle accelerate faster.
• (2H) is the default four-wheel drive mode. (4L) is not selectable in sport mode.
• The front electronic locking differential is not available in sport mode.
• The rear electronic locking differential is available.
• The stabilizer bar disconnect is not available in sport mode.

Slippery

• For less than ideal road conditions such as snow or ice covered roads. This mode can be used for crossing terrain where a firm surface is covered with loose, wet or slippery material. Slippery mode lowers throttle response and optimizes shifting for slippery surfaces.
• (4H) is the default four-wheel drive mode. Both four-wheel drive modes are selectable in slippery mode.
• The front electronic locking differential is available when in (4L).
• The rear electronic locking differential is available.
• The stabilizer bar disconnect is not available in slippery mode.

Sand

• For off-road driving on soft, dry sand or deep snow. This mode may help get your vehicle unstuck from deep snow or sand.
• (4H) is the default four-wheel drive mode. (4L) is selectable in sand mode.
• The front electronic locking differential is available when in (4L).
• The rear electronic locking differential is engaged when in sand mode and is available in all selectable four-wheel drive modes.
• The stabilizer bar disconnect is available in (4H) or (4L).

Mud/Ruts

• For off-road driving. This mode enhances vehicle performance to traverse muddy, rutted or uneven terrains.
• (4H) is the default four-wheel drive mode. (4L) is selectable in mud/rut mode.
• The front electronic locking differential is available when in four-wheel drive low.
• The rear electronic locking differential is engaged when in mud/ruts mode.
• The stabilizer bar disconnect is available in (4H) or (4L).

Rock Crawl

• For off-road driving and optimum rock-climbing ability. Rock crawl mode optimizes the throttle and transmission response to provide you additional control of your vehicle.
• (4L) is the only four-wheel drive mode selectable in rock crawl, the system prompts you to put your vehicle into (4L) upon selection.
• The front electronic locking differential is available when in (4L).
• The rear electronic locking differential is engaged when in rock crawl mode.
• The stabilizer bar disconnects when in rock crawl mode.

Baja

• For high speed off-road driving. Baja mode optimizes the throttle control for better response and torque delivery.
• (4H) is the default four-wheel drive mode.
• The front electronic locking differential is available when in (4L).
• The rear electronic locking differential is available
• The stabilizer bar disconnect is available in (4H) or (4L).

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