Any reason to not leave the advanced 4WD in 4A all the time?

[mneblett]

In older Fords, 4A left the front hubs engaged all the time, resulting in parasitic drag (a small mpg hit), and somewhat increased wear. Anyone know whether the front hubs will be constantly engaged in 4A, or -- with today's electronics -- are the hubs and the transfer case automatically engaged only when the system determines that toque needs to be delivered to the from wheels?

Normally, in response to a question like this, I would same "the car's not out yet, so nobody knows" -- but I would expect the current Ranger's system is the same, and someone may know how it works in 4A.

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[Lakelife36]

I was going to say fuel economy, but you already have that covered. I would also assume that 4A locks in the hubs and transfer case, and modulates the centre diff with EM clutches, then shifting to 4H locks the centre diff.

 

[jdogi]

The reason that I'll probably never use it is because I prefer to be in control when I drive. Surprises are not my friend. Other drivers may feel that the computers and mechanicals can do a better job deciding how/when various nannies should get engaged. This doesn't work for me.

If the traction is poor, I want to know that and I want to know it and feel it as early as possible. I can turn on 4H when I know I need it. I don't want a clutch to stealthily hide details of the conditions from me. Knowing them may well come in handy later... like when I go to brake.

 

[rtaylor]

In older Fords, 4A left the front hubs engaged all the time, resulting in parasitic drag (a small mpg hit), and somewhat increased wear. Anyone know whether the front hubs will be constantly engaged in 4A, or -- with today's electronics -- are the hubs and the transfer case automatically engaged only when the system determines that toque needs to be delivered to the from wheels?

Normally, in response to a question like this, I would same "the car's not out yet, so nobody knows" -- but I would expect the current Ranger's system is the same, and someone may know how it works in 4A.

You can leave it in 4A if you want. There are no disconnecting "hubs". The front driveshaft is live to the wheels, so there is parasitic drag in all modes including 2H (which allows fast on-the-fly switch to 4H or 4A). The transfer case uses an electric clutch pack to engage the front driveshaft. It probably doesn't have a mechanically-locked 4WD mode like Raptor (if it did, Ford would have been singing its praises), but rather just engages the electric clutch pack to maximum in 4H. Ford hasn't provided information on whether the clutch pack is modulated (partial engagement) to simulate AWD, or if it only has fast on/off control. My assumption is that it will work well, since this is one of the critical features of Bronco. The competition (Rubicon) also gets 4A option in 2021.

 

[mneblett]

You can leave it in 4A if you want. There are no disconnecting "hubs". The front driveshaft is live to the wheels, so there is parasitic drag in all modes including 2H (which allows fast on-the-fly switch to 4H or 4A). The transfer case uses an electric clutch pack to engage the front driveshaft. It probably doesn't have a mechanically-locked 4WD mode like Raptor (if it did, Ford would have been singing its praises), but rather just engages the electric clutch pack to maximum in 4H. Ford hasn't provided information on whether the clutch pack is modulated (partial engagement) to simulate AWD, or if it only has fast on/off control. My assumption is that it will work well, since this is one of the critical features of Bronco. The competition (Rubicon) also gets 4A option in 2021.

Thanks - no auto front locking hubs? My wife's last F-150 had pneumatic (vacuum) auto hubs. Gone on the Ranger? I'm a bit surprised, given the manufacturers' manic approach to gain hundredths of an mpg.

 

[Clump]

My GF has a new generation Jeep Compass. It does not have a 2WD mode, but under certain conditions it uses AWD and others FWD. When in FWD at low speeds it will engage the transfer case, so the rear driveshaft is spinning, but not engage the rear differential. This causes a fairly loud rumbling sound to come from the rear end. FCA has a flash that changes the behavior, but it just moves the noise to a higher speed. Apparently not a problem, or causing any damage, but the noise can be annoying.

 

[Rydfree]

The reason that I'll probably never use it is because I prefer to be in control when I drive. Surprises are not my friend. Other drivers may feel that the computers and mechanicals can do a better job deciding how/when various nannies should get engaged. This doesn't work for me.

If the traction is poor, I want to know that and I want to know it and feel it as early as possible. I can turn on 4H when I know I need it. I don't want a clutch to stealthily hide details of the conditions from me. Knowing them may well come in handy later... like when I go to brake.

The anti-lock brakes work well for , you know , when you have to brake .

 

[Mattwings]

Thanks - no auto front locking hubs? My wife's last F-150 had pneumatic (vacuum) auto hubs. Gone on the Ranger? I'm a bit surprised, given the manufacturers' manic approach to gain hundredths of an mpg.

The hub system and the transfer case are taken directly from the existing parts bin. The hubs lock through vacuum and the transfer case works exactly the same as the Raptor. There are several posts and explanations in other threads. The owners manual probably answers the question, but I would guess the hubs stay locked in 4A. It would be hard to engage the hubs quicker then the transfer case detects slip. If that’s the case, there is likely a small wear and fuel mileage hit.
The modes are slightly different in the Bronco, but this article gives you some idea- https://fordauthority.com/2017/05/f...rd-f-150-raptors-unique-awd4wd-transfer-case/

 

[PaulW]

4A is useful for certain driving conditions. For sure in the Bronco is will be identical to what has been used in the F150 for a few years.
On sandy pavement 4A will lessen the rear wheel slippage.
For sure on snow or wet pavement it is a necessary feature.
I have used it off road when in 2wd and I got a wheel up and 4A was a quick way to get moving. Engagement time was not an issue was every I used it in the pickup.
On the newer Raptors with the limited slip front it works fine.
The thing to remember is 4A is better for many conditions than 4wd or locked diffs.

 

[Gamecock]

Surprises are not my friend.

It minimizes "surprises", so you should love it. If you you don't like it, then you don't like it...but you're not some magically connected driver feeling every nuance and responding like an artistic genius to inputs and outputs.

 

[dgorsett]

It minimizes "surprises", so you should love it. If you you don't like it, then you don't like it...but you're not some magically connected driver feeling every nuance and responding like an artistic genius to inputs and outputs.

In defense of jdogi, a little wheel slip can alert a driver to road conditions that may not otherwise be obvious and driving or mode selection can be adjusted accordingly.

In defense of 4A, it can be real handy in variable road condition driving.

 

[Mattwings]

We each have our preference, but my experience with transfer cases with a automatic engagement is that it is much less “surprise” prone on snow and ice. The lack of front to rear differential can cause the front or rear to lock when it would not, if it was not “hard connected” in 4H. I have driven a lot in snow and ice, so overall it’s manageable for me, but given the choice, when I had it, I always found 4A more predictable and controllable when driving in varied terrain, particularly above trail speeds (20mph and above?). On the trail, purely focused on traction or working through obstacles or breaking trail on snow. 4H or 4L and most recently, occasionally locking my rear axle if I got stuck or close to stuck. I kind of use it as a fail safe. Leave the rear unlocked and if I need it, I know I am pushing either my or my vehicles capability. 4A for me, regardless of model.

 

[jdogi]

The anti-lock brakes work well for , you know , when you have to brake .

If I feel the ABS engaging, and it's a surprise to me, that's a fail. Yes it's a great feature, but it can't always save the day. It still increases stopping distance a ton vs having real traction.

You do you.

 

[jdogi]

We each have our preference, but my experience with transfer cases with a automatic engagement is that it is much less “surprise” prone on snow and ice. The lack of front to rear differential can cause the front or rear to lock when it would not, if it was not “hard connected” in 4H. I have driven a lot in snow and ice, so overall it’s manageable for me, but given the choice, when I had it, I always found 4A more predictable and controllable when driving in varied terrain, particularly above trail speeds (20mph and above?). On the trail, purely focused on traction or working through obstacles or breaking trail on snow. 4H or 4L and most recently, occasionally locking my rear axle if I got stuck or close to stuck. I kind of use it as a fail safe. Leave the rear unlocked and if I need it, I know I am pushing either my or my vehicles capability. 4A for me, regardless of model.

Well, I still reserve my right to change my mind on this. I did use "probably" in my opinion.

Like you, I'm a Michigander, and I've spent 3+ months every year for decades driving in the snow and ice. And I'm regularly testing the current conditions by intentionally causing wheel slip on acceleration to get a read for the surface conditions, this is a nearly constant habit that most of the time, I'm doing without even thinking about it. If I didn't do it, I'd need to drive at the "known" safe speed for the road conditions... conditions that I wouldn't really "know". So I'd be driving much slower than I'd want to.

And to the "you're no genius artist" guy... okay. Thanks for setting me straight. You've definitely helped me to recalibrate my confidence. I wouldn't have known how to drive if you hadn't fixed me. Thanks so much.

I should also confess. I've spend most of these winters driving overly light, overly powered, rear-wheel drive sports cars that most feel have no business being on the winter roads at all. So perhaps these skills and habits are just wasted when driving a heavy 4x4 truck. If so, I'll adapt. It's been more than a couple decades since I've driven a 4x4 on a daily basis and none of them had automatic transfer cases.

I encourage everyone to drive in the way that they find to be most safe for them. Trust your judgement and instincts... well, except for you Gamecock.

 

[Rydfree]

If I feel the ABS engaging, and it's a surprise to me, that's a fail. Yes it's a great feature, but it can't always save the day. It still increases stopping distance a ton vs having real traction.

You do you.

I remember the same arguments were made back when anti-lock started becoming the norm on sportbikes . A close friend always said he could stop quicker on regular brakes . He wasn't lying , I could also when you knew you were going to put that to the test . We both could do impressive stoppies at will , even at slick or sandy stop lights . Trouble is when conditions sneak up on you and then most people don't have the super human reaction time that they think they have to beat the computer . I rode that bike on the track for a whole season without crashing while he washed the front out 3 times ,lol .

That's me in the middle #41 on an old pre anti-lock bike , . I miss those bikes though as they were a hoot to slide around . I guess that's one argument against anti-lock

I'll take anti-lock any day now if it's available .

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